* Bump gomatrixserverlib
Mostly because I want to use Erik's go-faster jsoning.
* Update KeyDB for new KeyFetcher API
we now need to implement FetcherName.
* Attempt to fix integ tests
CanonicalJSON doesn't like the empty string, apparently, and anyway
canonicalising it is pointless.
* More integ test fix
* 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