* Fix response to /invite to match the format expected by synapse * gb vendor update github.com/matrix-org/gomatrixserverlib * Use gomatrixserverlib.RespInvite * gb vendor update github.com/matrix-org/gomatrixserverlib
* Use utility methods from gomatrixserverlib, rather than reimplementing them * Return string rather than pointer to string * Update gomatrixserverlib