Add ci workflow for validating schema changes

[optionsome]

Summary

Adds CI workflow that uses schema inspector to validate that there are no breaking schema changes and to list changes.

Issue

This was shortly discussed in a dev meeting this week

Unit tests

No

Documentation

No

Changelog

Skipped

[optionsome]

@leonardehrenfried perhaps we need to use a token? Seems like giving all permissions didn't fix the issue.

[leonardehrenfried]

I'm sorry but I don't have a clue.

[optionsome]

Maybe we need to use pull_request_target instead of pull_request for some reason but it does have some security concerns that I haven't fully looked into yet and action doesn't seem to run yet (perhaps the pr needs to be merged first).

[optionsome]

I read a bit more about pull_request_target and about the permissions in general. With pull_request_target we can circumvent the issues with permissions, but in this context it won't work since the workflow would run against the dev-2.x code instead of the pr code. Therefore, I think I'll try to implement this ci workflow with some js libraries instead of trying to use this action.

[optionsome]

I finally got it to work by manually running some npm cli library. This should be ready for review now.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.72%. Comparing base (1030408) to head (6016a89).
Report is 38 commits behind head on dev-2.x.

Additional details and impacted files

@@              Coverage Diff              @@
##             dev-2.x    #6396      +/-   ##
=============================================
- Coverage      69.73%   69.72%   -0.02%     
+ Complexity     18024    18016       -8     
=============================================
  Files           2057     2057              
  Lines          76970    76967       -3     
  Branches        7846     7844       -2     
=============================================
- Hits           53678    53666      -12     
- Misses         20545    20551       +6     
- Partials        2747     2750       +3     

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[optionsome]

Example failure https://github.com/opentripplanner/OpenTripPlanner/actions/runs/12871190149/job/35883925343