adjust CI env name & add Graph to README

[jGaboardi]

This PR:

• resolves update CI env naming conventions #749
• resolves update README with mention of Graph #750

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.2%. Comparing base (42a1832) to head (3aaaff9).
Report is 3 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #751   +/-   ##
=====================================
  Coverage   85.2%   85.2%           
=====================================
  Files        145     145           
  Lines      15635   15642    +7     
=====================================
+ Hits       13318   13326    +8     
+ Misses      2317    2316    -1     

see 1 file with indirect coverage changes