utils/github: Add date filtering to the commit author API query

[issyl0]

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• I missed the date filtering off the original implementation of the author API query - oops. This gives parity with the git log implementation.
• Also reduce verbosity of brew contributions --verbose a little since it annoyed me.

[BrewTestBot]

Review period will end on 2023-02-24 at 00:12:59 UTC.

[BrewTestBot]

Review period skipped due to critical label.

[MikeMcQuaid]

Thanks @issyl0! Making as critical because it fixes a bug (or at least non-obvious shortcoming)