fix: use VersionStr in model and add write test

[sergiusens]

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• Have you successfully run tox run -m lint?
• Have you successfully run tox run -e test-py310? (supported versions: py39, py310, py311, py312)

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.15%. Comparing base (6ff3e0b) to head (4f09926).
Report is 28 commits behind head on feature/craft-application.

Additional details and impacted files

@@                      Coverage Diff                      @@
##           feature/craft-application    #4626      +/-   ##
=============================================================
+ Coverage                      88.83%   89.15%   +0.32%     
=============================================================
  Files                            327      332       +5     
  Lines                          22033    22125      +92     
=============================================================
+ Hits                           19573    19726     +153     
+ Misses                          2460     2399      -61     

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