Release 0.8.0

Mon, 12 Dec 2022

Minor bugfix release, but due to lack of CI environments supporting old
Python versions, only Python 3.7+ is supported. Otherwise:

• @Snape3058 found some refcount issues (see issue #35), these have been
  fixed.
• Tested and enabled Python 3.10 support, dropped < 3.7.
• Various improvements to the CI environments.
• Move fully to setuptools (where available), in preparation for 3.12
  dropping distutils support.