Op pool and gossip for BLS to execution changes (#3726)

beacon_node/lighthouse_network/src/service/utils.rs

@@ -253,6 +253,7 @@ pub(crate) fn create_whitelist_filter(
         add(ProposerSlashing);
         add(AttesterSlashing);
         add(SignedContributionAndProof);
+        add(BlsToExecutionChange);
         for id in 0..attestation_subnet_count {
             add(Attestation(SubnetId::new(id)));
         }