Bump Microsoft.CodeAnalysis.CSharp from 4.4.0 to 4.6.0 (#174)

Bumps [Microsoft.CodeAnalysis.CSharp](https://github.com/dotnet/roslyn) from 4.4.0 to 4.6.0.
- [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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

src/Exercism.TestRunner.CSharp/Exercism.TestRunner.CSharp.csproj

@@ -10,7 +10,7 @@
     <PackageReference Include="CommandLineParser" Version="2.9.1" />
     <PackageReference Include="Exercism.Tests" Version="0.1.0-beta1" />
     <PackageReference Include="Humanizer.Core" Version="2.14.1" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.4.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="4.6.0" />
     <PackageReference Include="Newtonsoft.Json" Version="13.0.2" />
     <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="xunit.runner.utility" Version="2.4.2" />