MAINT: pyproject, pysat style updates

[jklenzing]

Description

Addresses #134, #131

• Updates to use pyproject.toml, readthedocs.yml, and improved github actions workflows.
• Removes checks on pre-pysat 3.0.4 versions.
• Replaces deprecated test instruments.
• Updates redirected xarray link in docs.
• Updates style to be compliant with flake8 6.1.0

NOTE: added backwards compat for pre-1.4 pandas for the operational server. pandas 1.1.5 is the maximum version supported there.

DOUBLE NOTE: The ICON TIEGCM feature is currently broken until pysatNASA 0.0.6 is released. Future fix in place with #132. This branch turns off testing temporarily until the next releases of pysat and pysatNASA are complete. TODO statements flag what needs to be updated. The pysatNASA cap of 0.0.4 is still required to trick the operational environment into behaving.

Uses the _test_new_tests instrument attribute to skip the multi-day tests for broken instruments, documented in #136. Implementation in pysat is in pysat/pysat#1166

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Tested against pysat 3.2.0 RC1 and pysat/pysat#1166

Test Configuration:

• Operating system: Ventura 13.6.1
• Version number: Python 3.10.9
• Any details about your local setup that are relevant: pysat 3.2.0 RC1

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

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

[aburrell]

Recommend keeping the version test, but add a max version for this as well.

if all([Version(pysat.__version__) > Version('3.0.1'),
        Version(pysat.__version__) < Version('3.2.0')]):
    inst_kwargs['use_header'] = True

[jklenzing]

Since the requirements files specifies a minimum of pysat 3.0.4, should we just proceed with the maximum cap?

[aburrell]

🤒 excellent point

[jklenzing]

LOL, just remembered why I didn't merge this one last month. The new tests flag wasn't finalized. Incoming PR