Bump Microsoft.CodeAnalysis.CSharp (#21)

Bumps [Microsoft.CodeAnalysis.CSharp](https://github.com/dotnet/roslyn) from 3.10.0-3.21254.9 to 3.10.0-3.21256.6.
- [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)

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

src/GitBuildInfo.SourceGenerator.csproj

@@ -40,7 +40,7 @@
   </ItemDefinitionGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.10.0-3.21254.9" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.10.0-3.21256.6" />
     <PackageReference Include="Nullable" Version="1.3.0" />
     <PackageReference Include="System.Text.Json" Version="6.0.0-preview.5.21255.7" />
   </ItemGroup>

tests/GitBuildInfo.SourceGenerator.Tests.csproj

@@ -6,7 +6,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.10.0-3.21254.9" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="3.10.0-3.21256.6" />
     <PackageReference Include="System.Text.Json" Version="6.0.0-preview.5.21255.7" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.4" />
     <PackageReference Include="xunit" Version="2.4.1" />