test minor artifact changes for backward + forward compatability

[MichelleArk]

resolves #9615

Problem

mashumaro (and so our BaseResource) class has support for forward and backward-compatible changes:

1. adding a field with a default value
2. removing a field with a default value

as in -- these changes are possible within a minor schema evolution, and would not break serialization / deserialization

However, if we are going to rely on these guaruntees we ought to test and document them!

Solution

Add unit tests for forward and backward compatability of minor schema evolutions, and update development docs to be more thorough.

Checklist

• I have read the contributing guide and understand what's expected of me
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• This PR has no interface changes (e.g. macros, cli, logs, json artifacts, config files, adapter interface, etc) or this PR has already received feedback and approval from Product or DX
• This PR includes type annotations for new and modified functions

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.19%. Comparing base (35062ca) to head (3b0041f).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #10066      +/-   ##
==========================================
- Coverage   88.20%   88.19%   -0.01%     
==========================================
  Files         181      181              
  Lines       22665    22665              
==========================================
- Hits        19991    19989       -2     
- Misses       2674     2676       +2     

Flag	Coverage Δ
integration	85.56% <ø> (ø)
unit	62.31% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.