Modify CLI build file to always ignore NU5104

Author: dagood

repos/cli.proj

@@ -117,6 +117,28 @@
                       Overwrite="true" />
   </Target>
 
+  <!--
+    Ignore this error in the CLI build, which doesn't seem to happen in ProdCon:
+
+      error NU5104: A stable release of a package should not have a prerelease dependency. Either
+      modify the version spec of dependency "NuGet.Frameworks [4.7.0-rtm.5156, )" or update the
+      version field in the nuspec.
+  -->
+  <Target Name="AddNoWarnNU5104ByDefault" BeforeTargets="Build">
+    <PropertyGroup>
+      <BuildDefaultsFile>$(ProjectDirectory)build\BuildDefaults.props</BuildDefaultsFile>
+      <ReplacementEndMark>&lt;/NoWarn&gt;</ReplacementEndMark>
+      <InsertItemLine>;NU5104$(ReplacementEndMark)</InsertItemLine>
+
+      <BuildDefaultsPropsContents>$([System.IO.File]::ReadAllText('$(BuildDefaultsFile)'))</BuildDefaultsPropsContents>
+    </PropertyGroup>
+
+    <WriteLinesToFile File="$(BuildDefaultsFile)"
+                      Lines="$(BuildDefaultsPropsContents.Replace('$(ReplacementEndMark)', '$(InsertItemLine)'))"
+                      Condition="! $(BuildDefaultsPropsContents.Contains('$(InsertItemLine)'))"
+                      Overwrite="true" />
+  </Target>
+
   <Target Name="CopyTarBall" AfterTargets="CopyPackage">
     <ItemGroup>
       <CliTarBalls Include="$(TarBallOutput)*$(TarBallExtension)" />