Display error if --ignore-warnings and --ignore-errors are passed in same command

[ernilambar]

wp plugin check hello-world --ignore-warnings --ignore-errors

In the CLI command plugin check, passing arguments --ignore-warnings and --ignore-errors at same time will always give empty results. We could warn if both arguments are passed.

[ernilambar]

Blocked by #153

[davidperezgar]

Should we finish this issue?

[ernilambar]

We should revisit this in the bigger refactor of CLI approach. #153