Update GitHub workflow

[FantasyTeddy]

Split the existing GitHub workflow into two distinct workflows:

• Build and Test:
  • Also executes dotnet test to ensure that no unit tests are broken.
  • Does not publish the NuGet packages anymore. (This also prevents the situation where a PR run will always fail, because an outside contributor does not have the NUGET_API_KEY secret set.)
• Publish NuGet package
  • Only executes on the main branch.

To consider:

• The "Publish NuGet package" workflow should probably have a different trigger than pushing on main, because this does not ensure that a new package version has been set.
  (The --skip-duplicate option on dotnet nuget push also indicates that this can lead to unexpected behavior; e.g. packages not actually being published with the intended version.)
• The dotnet build command in the "Publish NuGet package" workflow could be replaced by dotnet pack if the property GeneratePackageOnBuild is not set to true in the project files.

[cdavernas]

LGTM! Many thanks man!

For the trigger, I guess 'on tag' is indeed better than push. I'll make sure to add https://github.com/cbcrouse/Versioning.NET, which autoversions projects using commit messages.
The skip-duplicate option is an artefact from an old project I copy pasted the workflow from.

[FantasyTeddy]

Oh neat, I didn't know about the package you mentioned.

Glad I could help!