Bump Microsoft.CodeAnalysis.CSharp.Workspaces in /DocGpt.Vsix

Bumps [Microsoft.CodeAnalysis.CSharp.Workspaces](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.Workspaces
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

DocGpt.Roslyn/DocGpt.Roslyn.csproj

@@ -20,7 +20,7 @@
 
 	<ItemGroup>
 		<PackageReference Include="Azure.AI.OpenAI" Version="1.0.0-beta.17" />
-		<PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.11.0" />
+		<PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.12.0" />
 	</ItemGroup>
 
 	<ItemGroup>