chore: add readme and markdown to default lint

[maryliag]

Add the lint checks for markdown and readme to the npm run lint command, to align the local command with what is being executed on github workflow.

Without this change the lint was taking 31s, and after it took 33s, so I think the change is acceptable.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.75%. Comparing base (a4fcd26) to head (521e699).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2489   +/-   ##
=======================================
  Coverage   90.75%   90.75%           
=======================================
  Files         157      157           
  Lines        7734     7734           
  Branches     1591     1591           
=======================================
  Hits         7019     7019           
  Misses        715      715