Add release workflow for GitHub releases

[Goooler]

• Closes Can we create releases from tags?  #1818.
• Refs Integrate with GitHub releases spotless-changelog#10.

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Check the release results at:

• https://github.com/Goooler/spotless/releases/tag/lib/3.0.0.BETA1
• https://github.com/Goooler/spotless/releases/tag/gradle/7.0.0.BETA1
• https://github.com/Goooler/spotless/releases/tag/maven/2.44.0.BETA1

[Goooler]

Some Gradle tasks that were added for printing release notes and performing related actions may now be removed. Please check them.

[nedtwigg]

Amazing, this has been bothering me for a while. I didn't realize it was as easy as gh release create, but actually that makes sense that github actions has that already logged in.

The logic here is pretty complex. I might be misunderstanding, but it looks like we would want prerelease to true for ffurrer2/extract-release-notes? EDIT: I see from your example that it is already tested, so it must be right I guess

But either way, seems like a better approach is just for this task to call gh blah?

Maybe the API should look like this?

spotlessChanglog {
  afterPushExec "gh release create {{tag}} --title plugin-gradle --notes '{{unreleased}}'"
}

[Goooler]

1. Something like softprops/action-gh-release can do this release as well, I use GH CLI here as GH officially supports it.
2. ffurrer2/extract-release-notes is for extracting release notes from changelog files, there might be similar mechanisms implemented by other tools but GH, I filed an issue to Support parsing release notes from changelog files cli/cli#9276.
3. Yeah we can call gh release ... from the Gradle side, but the key point is how to obtain the release notes, this is why I introduce some action steps here.

[Goooler]

I just filed a new issue about the third part to diffplug/spotless-changelog#49.