Support gossipsub 1.2.0

[arnetheduck]

libp2p/specs#548 - this has been merged and IDONTWANT is officially part of the spec - the feature is formally only enabled in gossipsub 1.2.0, meaning we must start supporting that version as a protocol in order to receive IDONTWANT messages from other clients (putting the fields in 1.1 was a hack).

[diegomrsantos]

Is it enough to create a new version here

nim-libp2p/libp2p/protocols/pubsub/gossipsub/types.nim

Line 22 in 0911cb2

GossipSubCodec_10* = "/meshsub/1.0.0"

and add it here

nim-libp2p/libp2p/protocols/pubsub/gossipsub.nim

Line 197 in 0911cb2

g.codecs &= GossipSubCodec_10

?

[kaiserd]

Generally, yes.
We should also limit sending IDONTWANT to peers that support v 1.2.0.

Still, would make sense to just up the version number to fix the issue of not receiving IDONTWANT from 1.2 version impls.

Let's also double check our current implementation matches the spec.

[kaiserd]

work on this started in #1106

[ufarooqstatus]

Gossipsub-v1.2 specification suggest that we MAY cancel outstanding IWANT if we receive the message from some other peer

This specification also suggests that we SHOULD cancel any queued IWANT reply if we receive IDONTWANT from the requesting peer. IMO, we have this available in this draft PR