Update to aionbotocore 2.25.2 and fix #1091485

This merge request updates auibotocore to v2.25.2, needed by python3-s3fs that I'm packaging (see https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1122885).

The merge request also fixes #1091485 that is currently preventing the migration of the package to testing.

The switch to github sources in d/watch is needed because the source tarball in PyPi is missing some files that are necessary for testing.

Salsa CI has been enabled and there is a failure in the debrebuild job that, apparently, is not related to this merge request.