Feature Request: Generate a REVIEWERS file

[olbrich]

There are some useful Github actions (like https://github.com/fabasoad/reviewers-action), which will automatically assign code reviewers to PRs in addition to those specified in the CODEOWNERS file.

This can help with some use cases that CODEOWNERS doesn't handle well (for example, you can't require multiple codeowner reviews on the same file).

This gem could facilitate this tool by:

1. Making the location of the configuration file a CLI argument (so a duplicate config with a different name) could be used. (e.g., 'reviewers.yml').
2. Allowing the tag used for file annotations to be configurable (e.g., '@review' instead of '@team').
3. Allow validate to be less strict, so that files can opt in without having to adjust the owned globs and a @reviewer tag is not required.