MAINT: testing syntax

[jklenzing]

Description

Addresses pysat/pysat#1053, pysat/pysat#1042, pysat/pysat#1048

• Updates testing syntax to maintain pytest standards.
• Updates Github Actions syntax
• Removes nose requirements
• restores changelog from previous version
• Adds RC workflow

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Via Github Actions

Checklist:

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

If this is a release PR, replace the first item of the above checklist with the
release checklist on the pysat wiki:
https://github.com/pysat/pysat/wiki/Checklist-for-Release

[jklenzing]

Added a flake-8 cap to this branch since the latest version does not like how we invoke the ignore rules. Documented as part of standards upgrade in #43.

[jklenzing]

Went ahead and added the RC check to close out issues at pysat. Results of test are here: https://github.com/pysat/pysatCDF/actions/runs/3594442005

Added #44 to capture the updating Github Actions to include windows and mac tests. Probably best for these to be implemented after or during meson upgrades to the install procedure.

[rstoneback]

Thanks @jklenzing and @aburrell!