Reenable NuGet publishing to GitHub NuGet registry.

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```YAML
pushCSharpNuGetToGitHubPackageRegistry:
needs: testAndDeploy
if: github.event_name == 'push'
runs-on: windows-latest
steps:
- uses: actions/checkout@v1
with:
submodules: true
- uses: nuget/setup-nuget@v1
- name: Publish CSharp NuGet to GitHub Package Registry
run: |
dotnet build -c Release
dotnet pack -c Release
nuget source Add -Name "GitHub" -Source "https://nuget.pkg.github.com/linksplatform/index.json" -UserName linksplatform -Password ${{ secrets.GITHUB_TOKEN }}
nuget push **/*.nupkg -Source "GitHub" -SkipDuplicate
```

Find the GitHub Actions workflow containing the pushCSharpNuGetToGitHubPackageRegistry job and compare it with the YAML in the issue. Check the workflow's push conditions and package-publishing steps; it is done when a push can publish the C# NuGet package to the GitHub NuGet registry without breaking the existing testAndDeploy dependency.

Written by the indexing model from the issue text.