Improve ProtocResolver.java warnings

[ascopes]

• Rewrite Termux warning to be clearer.
• Convert "LATEST" exception into a warning to be more permissive.

[codecov]

Codecov Report

Attention: Patch coverage is 33.33333% with 2 lines in your changes missing coverage. Please review.

Project coverage is 87.58%. Comparing base (0326e60) to head (3b89baa).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...pes/protobufmavenplugin/protoc/ProtocResolver.java	33.34%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #509   +/-   ##
=======================================
  Coverage   87.58%   87.58%           
=======================================
  Files          40       40           
  Lines        1312     1312           
  Branches       89       89           
=======================================
  Hits         1149     1149           
  Misses        122      122           
  Partials       41       41           

Files with missing lines	Coverage Δ
...pes/protobufmavenplugin/protoc/ProtocResolver.java	70.28% <33.34%> (ø)