Allow newer python versions to test on MacOS mimicking Ubuntu workflows

[Mikejmnez]

This PR

• [x] Provides a temporal patch to the pickling issues described in #292. A better long term solution needs to address this.
• [x] Allows pydap to work with newer python version in both macOS and Windows env.
• [x] Updates the MacOS Python versions that the tests run on to align with the Ubuntu workflow. Thus addresses #256.
• [x] All tests pass on my local testing environment with python=3.10

There was an earlier effort to update the python versions for testing workflow on #283. This PR essentially allows that to happen. However, this PR does not address the issue raised in #292 with multiprocessing.Process and netcdf. But it allows for updated testing workflow by skipping tests that may fail on MacOS (there is no issue on Ubuntu / linux). A separate PR should address #292.

Suggestions are welcome. This can also be a draft PR, but I do think that there is merit in updating the testing (python) environment, while also identifying the issues with MacOS and Windows

[Mikejmnez]

This PR does not yet address the downstream issue in: pydata/xarray/#4348.

[Mikejmnez]

Lets also talk about a long term solution. My Python knowledge is limited and I wonder if moving from WSGI to Flask might be a good move overall since that might reduce the amount of lower level configuration we have to do.

Yeah. That makes sense to me. That should take place on a separate issue/PR.