MAINT: pyproject.toml, NEP29, Github Actions updates

[jklenzing]

Description

Addresses https://github.com/pysat/pysat/issues/1051

Support for setup.py in pip has been deprecated. This brings the package up to standard.

• Moves metadata and settings to pyproject.toml
• flake8 settings in setup.cfg
• Uses optional install syntax to deploy test and doc suites to github actions
• updates GA for new versions
• Fixes issue where NEP29 case reinstalls latest numpy anyway
• Update installation instructions

Changes in development flow

• version now specified in pyproject.toml. Code extracts __version__ from this
• requirements files no longer needed. maintained for python 3.6 systems
• local installation through pip install . or pip install -e . for development case
• build versions for pypi via python -m build
• pytest coverage options stored in pyproject.toml, will run by default

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How Has This Been Tested?

pip install -i https://test.pypi.org/simple/ pysatCDAAC==0.0.3.0

Checklist:

• [x] Make sure you are merging into the develop (not main) branch
• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes
• [x] Any dependent changes have been merged and published in downstream modules
• [x] Add a note to CHANGELOG.md, summarizing the changes
• [x] Update zenodo.json file for new code contributors

[jklenzing]

Putting this up for discussion. We should probably test this out on other packages before merging to be sure we have a consistent way forward.

[jklenzing]

Looks fine to me. The pull is still marked as draft. Any further planned changes?

Keeping it as draft until our next meeting. Figured we should all chat before major changes.

[jklenzing]

@aburrell, @rstoneback , @JonathonMSmith this is ready for review. Updated based on the changes in pysatNASA. Note that we don't have docs yet in this code (see #37).