* bump gomatrixserverlib
(changes to KeyFetcher and KeyDatabase interfaces)
* Store keys rather than json in the keydatabase
Rather than storing the raw JSON returned from a /keys/v1/query call in the
table, store the key itself.
This makes keydb.Database implement the updated KeyDatabase interface.
* 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
