chore(dfns): update dfn files in preparation for 3.7.0 release

[wpbonelli]

Add DFNs for GWE and PRT models and regenerate mf6 component classes

[codecov]

Codecov Report

Attention: Patch coverage is 52.30024% with 394 lines in your changes are missing coverage. Please review.

Project coverage is 66.2%. Comparing base (029a4e1) to head (9f6d1f8).
Report is 22 commits behind head on develop.

Additional details and impacted files

@@            Coverage Diff            @@
##           develop   #2195     +/-   ##
=========================================
- Coverage     68.3%   66.2%   -2.1%     
=========================================
  Files          260     294     +34     
  Lines        57947   58856    +909     
=========================================
- Hits         39611   39009    -602     
- Misses       18336   19847   +1511     

Files	Coverage Δ
flopy/mf6/modflow/__init__.py	100.0% <100.0%> (ø)
flopy/mf6/modflow/mfems.py	77.7% <ø> (ø)
flopy/mf6/modflow/mfgnc.py	92.0% <ø> (ø)
flopy/mf6/modflow/mfgwf.py	100.0% <ø> (ø)
flopy/mf6/modflow/mfgwfapi.py	47.3% <ø> (ø)
flopy/mf6/modflow/mfgwfbuy.py	55.5% <ø> (ø)
flopy/mf6/modflow/mfgwfchd.py	100.0% <ø> (ø)
flopy/mf6/modflow/mfgwfcsub.py	39.6% <ø> (ø)
flopy/mf6/modflow/mfgwfdis.py	100.0% <100.0%> (ø)
flopy/mf6/modflow/mfgwfdisu.py	100.0% <100.0%> (ø)
... and 96 more

... and 27 files with indirect coverage changes