[FR] Add support for querying Plugin Licenses by dateUpdated

[BenParizek]

It would be nice if there was a way to query results from the Plugin Licenses endpoint by dateUpdated.

Right now, there is no way of knowing the last date updates were made so (I believe) we need to query all entries from the API to know if a record was changed more recently than the last time we checked the API. The best partial query we can do is check for IDs after the last ID we know about, but that only helps us sync recent stuff and doesn't help us know about any change to an existing record from an older point in history (say, when someone updates a renewal status).

If we had a way to query by dateUpdated, we could track the last time we downloaded our plugin records locally, and just query for any changes that took place between the last query and the current query. Would make it a bit easier to try to maintain a sync of the data without having to re-query all the data on our end.