deps: Remove libp2p-pubsub dep replacment with custom fork

[Wondertan]

#409 introduces a custom pubsub fork which excludes one commit from that forces us to update to the newest go-datastore which forces us to upgrade to new IPLDv1. The upgrade should happen inevitably and this is the only right solution to the problem, however, on the time fork was made the decision was to go with a drastically less time-consuming approach, that wouldn't require refactoring the whole ipld pkg.

[Wondertan]

We are not using fork anymore