libp2p upgrade + gossipsub interval fix (#3012)

## Issue Addressed
Lighthouse gossiping late messages

## Proposed Changes
Point LH to our fork using tokio interval, which 1) works as expected 2) is more performant than the previous version that actually worked as expected
Upgrade libp2p 

## Additional Info
https://github.com/libp2p/rust-libp2p/issues/2497

beacon_node/lighthouse_network/src/service.rs

@@ -21,7 +21,7 @@ use libp2p::{
     swarm::{SwarmBuilder, SwarmEvent},
     PeerId, Swarm, Transport,
 };
-use open_metrics_client::registry::Registry;
+use prometheus_client::registry::Registry;
 use slog::{crit, debug, info, o, trace, warn, Logger};
 use ssz::Decode;
 use std::fs::File;