chore(deps): update dependency verify.nunit to 31.15.0 (#1184)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

Directory.Packages.props

@@ -28,7 +28,7 @@
     <PackageVersion Include="TUnit" Version="1.24.18" />
     <PackageVersion Include="TUnit.Core" Version="1.24.18" />
     <PackageVersion Include="Verify.MSTest" Version="31.15.0" />
-    <PackageVersion Include="Verify.NUnit" Version="31.14.0" />
+    <PackageVersion Include="Verify.NUnit" Version="31.15.0" />
     <PackageVersion Include="Verify.TUnit" Version="31.14.0" />
     <PackageVersion Include="Verify.XunitV3" Version="31.14.0" />
     <PackageVersion Include="xunit.runner.visualstudio" Version="3.1.5" />