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/discovery/mod.rs

@@ -927,24 +927,6 @@ impl<TSpec: EthSpec> NetworkBehaviour for Discovery<TSpec> {
         }
     }
 
-    fn inject_connected(&mut self, _peer_id: &PeerId) {}
-    fn inject_disconnected(&mut self, _peer_id: &PeerId) {}
-    fn inject_connection_established(
-        &mut self,
-        _peer_id: &PeerId,
-        _connection_id: &ConnectionId,
-        _endpoint: &ConnectedPoint,
-        _failed_addresses: Option<&Vec<Multiaddr>>,
-    ) {
-    }
-    fn inject_connection_closed(
-        &mut self,
-        _: &PeerId,
-        _: &ConnectionId,
-        _connected_point: &ConnectedPoint,
-        _handler: Self::ProtocolsHandler,
-    ) {
-    }
     fn inject_event(
         &mut self,
         _: PeerId,