Add CI lint job

[calda]

This PR adds a CI job to lint the code, using the same configuration as the local format.sh.

If only running tests via swift test, format.sh isn't currently run. We could potentially add a test that does this as a side-effect, but either way a CI job is reasonable.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.29%. Comparing base (37ac49c) to head (a54f956).
⚠️ Report is 2 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2420      +/-   ##
===========================================
- Coverage    95.29%   95.29%   -0.01%     
===========================================
  Files          164      164              
  Lines        25036    25036              
===========================================
- Hits         23858    23857       -1     
- Misses        1178     1179       +1     

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