Fixing the conflicts involved patching up some of the `block_hash` verification, the rest will be done as part of https://github.com/sigp/lighthouse/issues/3870
I've needed to do this work in order to do some episub testing. This version of libp2p has not yet been released, so this is left as a draft for when we wish to update. Co-authored-by: Diva M <divma@protonmail.com>