Fixing oldest OpenMDAO install

[kanekosh]

Purpose

This PR fixed the build with the oldest dependencies (specifically, the installation of OpenMDAO 3.15.0)

Expected time until merged

Soon

Type of change

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (non-backwards-compatible fix or feature)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Documentation update
• Maintenance update
• Other (please describe)

Testing

Checklist

• I have run flake8 and black to make sure the Python code adheres to PEP-8 and is consistently formatted
• I have formatted the Fortran code with fprettify or C/C++ code with clang-format as applicable
• I have run unit and regression tests which pass locally with my changes
• I have added new tests that prove my fix is effective or that my feature works
• I have added necessary documentation

[codecov]

Codecov Report

Merging #412 (853b2e3) into main (9f592ae) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #412   +/-   ##
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  Coverage   94.52%   94.52%           
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  Files         103      103           
  Lines        6412     6412           
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  Hits         6061     6061           
  Misses        351      351           

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[eytanadler]

Does the old wheel version automatically use an older pip? Why is the old pip version no longer necessary?

[kanekosh]

Since I dropped --upgrade the pip is not upgraded to the latest. On my local machine, the build also worked with the newer pip (23.1.2), but I don't think we need the latest pip for the oldest build.

The pip version no longer matters here because with the older wheel, we can now build the wheel for OpenMDAO==3.15.0, thus no need to revert to the legacy setup.py install (that was the reason I pinned to the old pip version previously).

[eytanadler]

Since I dropped --upgrade the pip is not upgraded to the latest. On my local machine, the build also worked with the newer pip (23.1.2), but I don't think we need the latest pip for the oldest build.

The pip version no longer matters here because with the older wheel, we can now build the wheel for OpenMDAO==3.15.0, thus no need to revert to the legacy setup.py install (that was the reason I pinned to the old pip version previously).

Makes sense, good find. I'm going to give this a shot on mdolab/openconcept#53 too.