Allow ignoring files using regex pattern

[rcontreras-te]

We have a project that is using an older version of mockery where mocks are generated at a per file basis. (usually named mock_*.go). It would be nice to be able to ignore these files when generating docs. If they all resided in a single directory we'd be able to use --exclude-dirs but since they, much like unit tests, reside alongside the code, that isn't possible.

Is it possible to introduce another option to cover a case like this? --exclude-files=REGEX where we could add something like --exclude-files='mock_.*'?