add schema checking test

[gilesknap]

• update the schema files to represent the current state of the pydantic models
• add a test to make sure these always get updated

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 44.41%. Comparing base (32ef01f) to head (d25a2b8).

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #24      +/-   ##
==========================================
+ Coverage   42.55%   44.41%   +1.86%     
==========================================
  Files          23       23              
  Lines         860      860              
==========================================
+ Hits          366      382      +16     
+ Misses        494      478      -16     

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[gilesknap]

@MJGaughran can we merge this one now?