Replace deprecated GA action with action-gh-release for generating the release

[michaelmell]

• Move from using to https://github.com/actions/upload-release-asset (deprecated/unmaintained) to e.g.: https://github.com/softprops/action-gh-release for creating the release.
• Currently we use a deprecated version. I will need to fix this eventually. See this code comment.

[ehrenfeu]

This is a duplicate of #4, no?

I'd prefer to use "official" actions over custom ones (softprops) to avoid the constant need of updating workflows if some foreign action is no longer maintained...