pydoas 2.0.0

This release modernises the source code to support python versions 3.10-3.13. Note that with this release, support for python 2.7 is deprecated.

What's Changed

• Catch up with recent python versions and deprecate python 2.7 by @jgliss in #1
• use setuptools_scm for version control by @jgliss in #2

Full Changelog: v1.2.2...2.0.0