Update model default start year

[jdebacker]

This PR updates the default start year to 2024.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (da5e895) to head (e780bc4).

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Additional details and impacted files

@@            Coverage Diff            @@
##            master      #382   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           11        11           
  Lines         1109      1109           
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  Hits          1109      1109           

Flag	Coverage Δ
unittests	100.00% <100.00%> (ø)

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Files	Coverage Δ
ccc/utils.py	100.00% <100.00%> (ø)