refactor(shapefile_utils): warn if fieldname truncated per 10 char limit

[wpbonelli]

• feature: Allow for user defined attribute columns in modpath shapefile export.  #1977 (comment)

[codecov]

Codecov Report

Merging #2003 (c115c12) into develop (af8954b) will increase coverage by 0.0%.
Report is 1 commits behind head on develop.
The diff coverage is 100.0%.

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #2003   +/-   ##
=======================================
  Coverage     72.7%   72.7%           
=======================================
  Files          258     258           
  Lines        58828   58833    +5     
=======================================
+ Hits         42797   42803    +6     
+ Misses       16031   16030    -1     

Files	Coverage Δ
flopy/export/shapefile_utils.py	83.7% <100.0%> (+0.2%)	⬆️

... and 1 file with indirect coverage changes