packagist: Canonicalize github origins
In particular, there seems to be a negligeable number of origins using SSH instead of HTTPS, which the git loader cannot deal with.
https://sentry.softwareheritage.org/share/issue/709325715f6d44cdbb7cc27a244a472a/
Test Plan
Build fails because it depends on swh-core!295 (closed)
Migrated from D8673 (view on Phabricator)