Bump Microsoft.CodeAnalysis.CSharp from 4.11.0 to 4.12.0

Bumps [Microsoft.CodeAnalysis.CSharp](https://github.com/dotnet/roslyn) from 4.11.0 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

@@ -38,7 +38,7 @@
         <PackageVersion Include="Meziantou.Xunit.ParallelTestFramework"
                         Version="2.3.0" />
         <PackageVersion Include="Microsoft.CodeAnalysis.CSharp"
-                        Version="4.11.0" />
+                        Version="4.12.0" />
         <PackageVersion Include="Microsoft.NET.Test.Sdk"
                         Version="17.12.0" />
         <PackageVersion Include="NuGet.Versioning"