chore(format): apply isort rule, update default rules

[wpbonelli]

• extend default rules in pyproject.toml
• apply import sorting
• fix line lengths: demo what's needed to fully observe E501
  • flopy/version.py
  • update_version.py
  • flopy/utils/zonbud.py
• ignore other line length violations in comments for now

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.0%. Comparing base (aa9f410) to head (e2c4299).

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #2137   +/-   ##
=======================================
  Coverage     73.0%   73.0%           
=======================================
  Files          260     260           
  Lines        59483   59483           
=======================================
  Hits         43482   43482           
  Misses       16001   16001           

Files	Coverage Δ
flopy/utils/modpathfile.py	88.4% <100.0%> (ø)
flopy/utils/particletrackfile.py	96.0% <100.0%> (ø)
flopy/utils/zonbud.py	66.8% <ø> (ø)
flopy/version.py	100.0% <ø> (ø)