Add support to create pre-releases with a generated changelog

[NotTheEvilOne]

What this PR does / why we need it:
This PR enhances existing tooling to handle GitHub releases and adds support to generate a changelog for new releases of the python-gardenlinux-lib.

Which issue(s) this PR fixes:
Fixes #229
Fixes gardenlinux/gardenlinux#3800
Superseeds #210
Superseeds #230

[codecov]

Codecov Report

❌ Patch coverage is 88.61789% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.67%. Comparing base (95a3985) to head (ab3b929).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/gardenlinux/github/release/__main__.py	70.37%	8 Missing ⚠️
src/gardenlinux/github/release/release.py	92.42%	5 Missing ⚠️
src/gardenlinux/github/client.py	95.83%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #271      +/-   ##
==========================================
- Coverage   91.55%   90.67%   -0.88%     
==========================================
  Files          42       45       +3     
  Lines        2083     2210     +127     
==========================================
+ Hits         1907     2004      +97     
- Misses        176      206      +30     

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[yeoldegrove]

Overall, nice work! See some nitpicks.
Also, we need some kind of written document how the release process works and how to push out a new release.

[NotTheEvilOne]

It would be great if this PR adds a written document on how (pre-)releases are created and which steps this includes.

Added with https://github.com/gardenlinux/python-gardenlinux-lib/blob/7c408ace805de2a8559fc31be2abbb6abd4d1ae9/docs/release.rst

[yeoldegrove]

It would be great if this PR adds a written document on how (pre-)releases are created and which steps this includes.

Added with https://github.com/gardenlinux/python-gardenlinux-lib/blob/7c408ace805de2a8559fc31be2abbb6abd4d1ae9/docs/release.rst

Could we extend this a bit so that it really also talks about the actual steps to be taken?

• Bump Versions in which files and why?
  • e.g. :since: 0.7.0
  • pyproject.toml
  • .github/actions/*/*.yml
• Command to do the tagging
• How to use a new release in projects that consume the lib?