make map key case sensitive configurable

[ktong]

No description provided.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 86.9%. Comparing base (621f586) to head (742dc78).
Report is 35 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #365     +/-   ##
=======================================
+ Coverage   82.8%   86.9%   +4.1%     
=======================================
  Files         62      27     -35     
  Lines       2649    1199   -1450     
=======================================
- Hits        2195    1043   -1152     
+ Misses       371     144    -227     
+ Partials      83      12     -71     

Files	Coverage Δ
config.go	100.0% <100.0%> (ø)
internal/maps/transform.go	100.0% <100.0%> (ø)
option.go	100.0% <100.0%> (ø)

... and 35 files with indirect coverage changes