testing/woodpecker: move maintainership to Will Sinatra

Hello :) I would like to resign as maintainer of the woodpecker aport.

I once had planned to use it myself many months ago but switched to a different CI system in the end. I believe the maintainer of a package should be a user of it and I do not see much sense in remaining maintainer as it will just lead to late updates.

This only applies to woodpecker, I'll happily keep maintaining any other aport that's currently on me! :D