[pigeon]: Bump org.jetbrains.kotlin:kotlin-gradle-plugin from 1.8.20 to 1.8.21 in /packages/pigeon/platform_tests/test_plugin/android (flutter#3824)

Bumps [org.jetbrains.kotlin:kotlin-gradle-plugin](https://github.com/JetBrains/kotlin) from 1.8.20 to 1.8.21.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a href="https://github.com/JetBrains/kotlin/releases">org.jetbrains.kotlin:kotlin-gradle-plugin's releases</a>.</em></p>
<blockquote>
<h2>Kotlin 1.8.21</h2>
<h2>Changelog</h2>
<h3>Compiler</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-57848"><code>KT-57848</code></a> Native: compilation of dynamic/static library fails with Xcode 14.3</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-57875"><code>KT-57875</code></a> Native compilation failure: Suspend functions should be lowered out at this point, but FUN LOCAL_FUNCTION_FOR_LAMBDA</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-57946"><code>KT-57946</code></a> KAPT: &quot;RuntimeException: No type for expression&quot; with delegate</li>
</ul>
<h3>JavaScript</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-57356"><code>KT-57356</code></a> KJS: StackOverflowException on <code>@JsExport</code> with type parameters referring to one another</li>
</ul>
<h3>Tools. Commonizer</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-57796"><code>KT-57796</code></a> NoSuchFileException in :module-B:commonizeCInterop with Kotlin 1.8.20</li>
</ul>
<h3>Tools. Compiler plugins. Serialization</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-58067"><code>KT-58067</code></a> Serialization: NullPointerException caused by <code>@contextual</code> property with type with generic</li>
</ul>
<h3>Tools. Gradle. JS</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-57766"><code>KT-57766</code></a> KJS / Gradle &quot;Module not found: Error: Can't resolve 'kotlin-kotlin-stdlib-js-ir'&quot; when using &quot;useEsModules&quot;</li>
</ul>
<h3>Tools. Kapt</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-58027"><code>KT-58027</code></a> Kotlin 1.8.20 kapt issue &quot;null: KtCallExpression: build()&quot;</li>
</ul>
<h3>Tools. Maven</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-58048"><code>KT-58048</code></a> Maven: &quot;Too many source module declarations found&quot; after upgrading to 1.8.20</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-58101"><code>KT-58101</code></a> 'Unable to access class' in kotlin-maven-plugin after updating to Kotlin 1.8.20</li>
</ul>
<h2>Checksums</h2>
<table>
<thead>
<tr>
<th>File</th>
<th>Sha256</th>
</tr>
</thead>
<tbody>
<tr>
<td>kotlin-compiler-1.8.21.zip</td>
<td>6e43c5569ad067492d04d92c28cdf8095673699d81ce460bd7270443297e8fd7</td>
</tr>
<tr>
<td>kotlin-native-linux-x86_64-1.8.21.tar.gz</td>
<td>0fc854641dd6d88dce3cc044bb5bc99b9035480474e23541eff03771690c68cf</td>
</tr>
<tr>
<td>kotlin-native-macos-x86_64-1.8.21.tar.gz</td>
<td>e73bfdac0461ee0c84f25e61063c243bf8d4eb8e0ff5da250456d6a23c677fd6</td>
</tr>
<tr>
<td>kotlin-native-macos-aarch64-1.8.21.tar.gz</td>
<td>0a97957921ed55458f3e6cc9117643914ccf3663d8ad7eb161a4a03035a7521b</td>
</tr>
<tr>
<td>kotlin-native-windows-x86_64-1.8.21.zip</td>
<td>f23d3288a47ee580f82f862d55452a75074fce3d26fe7e7f55e27b6015226d8d</td>
</tr>
</tbody>
</table>
</blockquote>
</details>
<details>
<summary>Changelog</summary>
<p><em>Sourced from <a href="https://github.com/JetBrains/kotlin/blob/master/ChangeLog.md">org.jetbrains.kotlin:kotlin-gradle-plugin's changelog</a>.</em></p>
<blockquote>
<h2>1.8.21</h2>
<h3>Compiler</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-57848"><code>KT-57848</code></a> Native: compilation of dynamic/static library fails with Xcode 14.3</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-57875"><code>KT-57875</code></a> Native compilation failure: Suspend functions should be lowered out at this point, but FUN LOCAL_FUNCTION_FOR_LAMBDA</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-57946"><code>KT-57946</code></a> KAPT: &quot;RuntimeException: No type for expression&quot; with delegate</li>
</ul>
<h3>JavaScript</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-57356"><code>KT-57356</code></a> KJS: StackOverflowException on <a href="https://github.com/JsExport"><code>@�JsExport</code></a> with type parameters referring to one another</li>
</ul>
<h3>Tools. Compiler plugins. Serialization</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-58067"><code>KT-58067</code></a> Serialization: NullPointerException caused by <a href="https://github.com/Contextual"><code>@�Contextual</code></a> property with type with generic</li>
</ul>
<h3>Tools. Gradle. JS</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-57766"><code>KT-57766</code></a> KJS / Gradle &quot;Module not found: Error: Can't resolve 'kotlin-kotlin-stdlib-js-ir'&quot; when using &quot;useEsModules&quot;</li>
</ul>
<h3>Tools. Kapt</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-58027"><code>KT-58027</code></a> Kotlin 1.8.20 kapt issue &quot;null: KtCallExpression: build()&quot;</li>
</ul>
<h3>Tools. Maven</h3>
<ul>
<li><a href="https://youtrack.jetbrains.com/issue/KT-58048"><code>KT-58048</code></a> Maven: &quot;Too many source module declarations found&quot; after upgrading to 1.8.20</li>
<li><a href="https://youtrack.jetbrains.com/issue/KT-58101"><code>KT-58101</code></a> 'Unable to access class' in kotlin-maven-plugin after updating to Kotlin 1.8.20</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a href="https://github.com/JetBrains/kotlin/commit/ec1553ae4123974f50f4f18a1b6f2656cac2dde1"><code>ec1553a</code></a> Add Changelog for 1.8.21</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/92c7d495e51fee8c5ec16631576c43d9e59d64e1"><code>92c7d49</code></a> [Maven] Filter duplicated source roots to avoid multiple module declarations ...</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/035172c30d47102138e3c9253587ae8481aba219"><code>035172c</code></a> [KxSerialization] Fix &quot;IllegalAccessError: Update to static final field&quot;</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/ea2e0bdc3ffd91661bd7dca599448dfda0b76925"><code>ea2e0bd</code></a> Fix maven script executor after changes in the jdk path processing</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/d44d8ea1a7ee3947964119070e4ae55b651f4bb1"><code>d44d8ea</code></a> Kapt+JVM_IR: generate delegated members correctly</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/ebdbaab6d8318ea2e9583681c3e4e0a487a514b1"><code>ebdbaab</code></a> Correctly support nullability in type arguments for serializer&lt;T&gt;() intrinsic.</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/34efee5474ac6bb56af53487b75a20e35d54399b"><code>34efee5</code></a> Don't fail if there is no serializer for type parameters of contextual serial...</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/a75271c97e61bcb4918ddf27cf4ff408fceafbb8"><code>a75271c</code></a> Do not create cacheableChildSerializers unless it is necessary</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/9f94142179eaa3fa2fd1ac2ba90cd191cfdb8795"><code>9f94142</code></a> [K/JS] Rework ES modules part with squashed JsImport and right renaming strat...</li>
<li><a href="https://github.com/JetBrains/kotlin/commit/153d7b9d6fe506380796e8245350ac2cdab74570"><code>153d7b9</code></a> [K/JS] Change strategy for implicitly exported declarations if there is a cyc...</li>
<li>Additional commits viewable in <a href="https://github.com/JetBrains/kotlin/compare/v1.8.20...v1.8.21">compare view</a></li>
</ul>
</details>
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packages/pigeon/platform_tests/test_plugin/android/build.gradle

@@ -2,7 +2,7 @@ group 'com.example.test_plugin'
 version '1.0-SNAPSHOT'
 
 buildscript {
-    ext.kotlin_version = '1.8.20'
+    ext.kotlin_version = '1.8.21'
     repositories {
         google()
         mavenCentral()