Release 0.3.0

[rhpvorderman]

Release checklist

• [x] Check outstanding issues on JIRA and Github.
• [x] Check latest documentation looks fine.
• [x] Create a release branch.
  • [x] Set version to a stable number.
  • [x] Change current development version in CHANGELOG.rst to stable version.
  • [x] Change the version in __init__.py
• [x] Merge the release branch into main.
• [x] Created an annotated tag with the stable version number. Include changes from CHANGELOG.rst.
• [x] Push tag to remote. This triggers the wheel/sdist build on github CI.
• [x] merge main branch back into develop.
• [x] Add updated version number to develop. (setup.py and src/zlib_ng/__init__.py)
• [x] Build the new tag on readthedocs. Only build the last patch version of each minor version. So 1.1.1 and 1.2.0 but not 1.1.0, 1.1.1 and 1.2.0.
• [x] Create a new release on github.
• [x] Update the package on conda-forge.