Fix a SSINS test for future pyuvdata compatibility

[bhazelton]

Description

This fixes several things that will break for pyuvdata>=v3.0, including going to future shapes always.

I made some minor tweaks to the GitHub actions yaml to speed up CI.

Checklist:

Main Code Body Checklist:

• Add or update docstring related to code change
• Add a unit test that verifies the efficacy of the code
• Write a tutorial if the feature would be useful to others to use
• Update CHANGELOG.md

Scripts Checklist:

• Add useful help strings for any arguments that are parsed
• Manually check that the script runs and gives proper results
• Update CHANGELOG.md

[mwilensky768]

Thanks @bhazelton . Other than random fails due to something with setuptools_scm (tersely documented in #126), this is passing and looks good. Will merge when the ubuntu builds finish.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (8991688) to head (e76e44e).

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Additional details and impacted files

@@            Coverage Diff            @@
##            master      #125   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            8         8           
  Lines          918       918           
=========================================
  Hits           918       918           

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[mwilensky768]

Thanks for the futureproofing! This is so so helpful. I'm going to merge now.