Bump Microsoft.CodeAnalysis.CSharp from 4.8.0 to 4.12.0

Bumps [Microsoft.CodeAnalysis.CSharp](https://github.com/dotnet/roslyn) from 4.8.0 to 4.12.0.
- [Release notes](https://github.com/dotnet/roslyn/releases)
- [Changelog](https://github.com/dotnet/roslyn/blob/main/docs/Breaking%20API%20Changes.md)
- [Commits](https://github.com/dotnet/roslyn/commits)

---
updated-dependencies:
- dependency-name: Microsoft.CodeAnalysis.CSharp
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Directory.Packages.props

@@ -23,6 +23,6 @@
     <PackageVersion Include="NUnit3TestAdapter" Version="5.0.0" />
 
     <!-- To resolve dependency conflict with GirCore.GObject-2.0.Integration and BenchmarkDotNet -->
-    <PackageVersion Include="Microsoft.CodeAnalysis.CSharp" Version="4.8.0" />
+    <PackageVersion Include="Microsoft.CodeAnalysis.CSharp" Version="4.12.0" />
   </ItemGroup>
 </Project>