message: test: use ipv6_only IPv6 addresses in custom cluster integration tests.
  Needed for IPv6-only environments such as Google.
  Risk level: Low
  Testing: custom_cluster_integration_test in IPv6 only environment.
diff: @@ -19,7 +19,7 @@ void CustomStaticCluster::startPreInit() {
  inline Upstream::HostSharedPtr CustomStaticCluster::makeHost() {
  Network::Address::InstanceConstSharedPtr address =
  - Network::Utility::parseInternetAddress(address_, port_, false);
  + Network::Utility::parseInternetAddress(address_, port_, true);
  return Upstream::HostSharedPtr{new Upstream::HostImpl(
  this->info(), "", address, this->info()->metadata(), 1,
  envoy::api::v2::core::Locality::default_instance(),
  