Documentation for shellcheck should include that it is configurable with a .shellcheckrc

[tonyfruzza]

Describe the solution you'd like
A simple README.md update is needed to clarify that in addition to the --enable flag, the .shellcheckrc can be used to configure additional entries.

Describe alternatives you've considered
Linking directly to the shellcheck documentation

Additional context
Allow for passing cli args directly through to shellcheck

Other shellcheck flags can not be passed through.

Which is true, but is misleading to those looking for an option to set disable entries.