Feature Request: Define exit code for warnings

Proposal

Add a --warning-exit-code=123 or similar option to define the exit code for warnings.

Background

If I understood correctly, react-doctor always exits with 0 or 1. Per default, on errors it gives 1, otherwise it will return with 0. This can be changed by setting --blocking warning.

Now when running e.g. in GitLab CI, I set --blocking error(default), which fails the CI and therefore works as a quality gate. However, warnings are also important and should be handled optimally. However, I barely read the Job output when everything is green, so I won't notice them usually.

With the above option I could add this to my CI definition:

  allow_failure:
    exit_codes: 123

If errors are found, this will result in a Job with a Warning Symbol in my CI though not failing the CI and blocking the Merge.