Document release process and include actual release notes in Changelog file

[weiji14]

The release process doesn't appear to be documented very well (e.g. with a checklist). The past few release PRs did not have without any description (e.g. #68, #73, #76), and the changelog page at https://tudelftgeodesy.github.io/sarxarray/CHANGELOG/ simply points to https://github.com/TUDelftGeodesy/sarxarray/releases even though it states "All notable changes to this project will be documented in this file".

sarxarray/docs/CHANGELOG.md

Lines 1 to 6 in 3a11cd0

	# Change Log
	All notable changes to this project will be documented in this file.
	This project adheres to [Semantic Versioning](http://semver.org/).
	See [releases](https://github.com/TUDelftGeodesy/sarxarray/releases) in the sarxarray repository for more details.

Recommendations:

1. Actually include release notes in CHANGELOG.md (refer to https://www.pyopensci.org/python-package-guide/documentation/repository-files/changelog-file.html on formatting)
2. Create a checklist, possibly as an Issue/Pull Request template, so that maintainers know how to create a release. Include steps such as:
   • Update CHANGELOG.md file
   • Update version in pyproject.toml
   • Create release/tag at https://github.com/TUDelftGeodesy/sarxarray/releases

Note that these are only suggestions, and you're welcome to implement some or all of the above 🙂 There are also other 'advanced' methods of e.g. updating the version based on git tags (https://www.pyopensci.org/python-package-guide/package-structure-code/python-package-versions.html#tool-3-setuptools-scm-versioning-using-git-tags), but up to you on what you're comfortable with implementing.

Part of JOSS review at openjournals/joss-reviews#10492

[rogerkuou]

Hi @weiji14 , sorry for being a bit silent recently, was occupied by other tasks.

I just worked on this issue via #103 . While addressing your awesome suggestions, I could not help to think if LLM agent can help with generating CHANGELOG info. I implemented an agent skill for this, but still leave reviewing and committing to human.

While my colleague is reviewing this PR, feel free to share your thoughts!