`aur-out-of-date` upstream providers

[AladW]

aur-out-of-date has a few upstream providers that are not included here:

https://github.com/simon04/aur-out-of-date/tree/master/upstream

namely perl, gitea, npmjs and rubygems. These look straightforward, so it might be worthwhile to include them in bumper as well.

[bcyran]

I would definitely like to have more providers in bumper but unfortunately it's unlikely I will implement this due to personal time constraints and priorities. This applies to #5 as well. I would be very happy to accept PRs though. I think it would be a perfect feature to contribute for someone from outside as the change would be very self contained and there are existing providers to take example from.