Add a working GitHub Actions config (for CI builds)

[janusw]

This PR updates the existing GHA config so that it triggers CI jobs for pushes to all branches and all PRs.

You can see a working GHA build based on this branch in my fork: https://github.com/janusw/GeoJSON.Net/actions/runs/7409092782

One can certainly add further extensions to this, but I'm deliberately sticking to the bare minimum that is necessary for triggering successful CI builds here (without any actual source-code changes), so that one has a baseline for further changes.

@xfischer @matt-lethargic Is this ok with you?

[janusw]

Ping! Is this repo dead? Can I help with maintenance? Or do I need to fork?

[xfischer]

Sorry for the delay @janusw and thanks again. Repo is not dead, but our day to day job and life leaves small space at some moments !

[xfischer]

Related discussion in #167 (comment)_

[janusw]

Sorry for the delay @janusw and thanks again.

Thanks for merging!

Repo is not dead, but our day to day job and life leaves small space at some moments !

I know that feeling ;)

[janusw]

Related discussion in #167 (comment)_

Yes, now that this issue is out of the way (and the tests are automatically run as part of the CI), I'm going to return to #167 and finish it up by adding a test case.

[matt-lethargic]

Hey @janusw sorry about any delay, I've not been able to look at this due to my day job.

Thanks @xfischer for looking at this. Maybe it's time to for me to step aside and look for a new maintainer :-/

[janusw]

Thanks @xfischer for looking at this.

+1

Maybe it's time to for me to step aside and look for a new maintainer :-/

Well, I can offer to help out with maintenance a bit, and support @xfischer in this task (if that is desired).

Currently you guys are certainly not living up to the promise given in the README ;)

We try and review most pull requests within a couple of days.

Fortunately it seems like this library is rather stable and does not need a huge amount of maintenance (which is a bit in contrast to the fact that all the latest releases on nuget.org have an -rc suffix).

Let me know if I can be of any help ...