Minor fix to mesh generator

[kanekosh]

Purpose

OAS mesh generator currently only accepts the chordwise discretization nx to be 2 or an odd number because of how it generates the cosine spacing in the chordwise direction. This PR fixes the mesh generator to make it work with even numbers for nx.

I also realized a weird behavior for rectangle wings: the default chordwise coordinate for [LE, TE] was [0, chord] when nx=2 and [-chord/2, chord/2] when nx >= 3. Now I fixed it, and the default coordinate is [0, chord] for any nx. I adjusted a few test cases accordingly because it affects CM computation.

Also made a minor edit to the GHA setting so that the "latest" build continues even if the "oldest" job fails, and vice versa.

Closes #378

Mesh examples

Expected time until merged

Week

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

[kanekosh]

Codecov is failing, but it's ready for review.

[eytanadler]

This makes the code both simpler and more general, very nice! (Nevermind about bumping the patch, I got it)

If you don't mind, I have a couple things to try with GHA to try to get codecov working that I'll add here. No guarantees that it'll work though.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.94%. Comparing base (d788e11) to head (29fe136).
Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #430      +/-   ##
==========================================
+ Coverage   93.92%   93.94%   +0.02%     
==========================================
  Files         104      104              
  Lines        6472     6461      -11     
==========================================
- Hits         6079     6070       -9     
+ Misses        393      391       -2     

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[sabakhshi]

These changes make sense. The inconsistent chordwise positioning of the wing added extra complexity when doing stability analysis. These changes will break my 740 code as result but they are for the better.

[kanekosh]

@sabakhshi I'm planning on adding a stability-constrained example to the docs, so I'll document the origin of the chordwise coordinate at that time.