Declare support for Matrix 1.8

[matrixbot]

This issue was originally created by @S7evinK at matrix-org/dendrite#3226.

Complete changelog v1.8

Client-Server API

Backwards Compatible Changes

• Require callers to be joined to the room to report its events, as per MSC2249.
  • No /report endpoint at all (see Declare support for Matrix 1.1 matrix-org/dendrite#3216)

Spec Clarifications

• Allow null in room_types in POST /publicRooms endpoints schemas. (#1564)
  • No filtering atm (see Declare support for Matrix 1.4 matrix-org/dendrite#3222)

Server-Server API

Deprecations

• Deprecate matrix SRV lookup steps during server discovery, as per MSC4040.
  • Support MSC4040 SRV lookups matrix-org/gomatrixserverlib#411

Backwards Compatible Changes

• Add matrix-fed SRV lookup steps to server discovery, as per MSC4040.
  • Support MSC4040 SRV lookups matrix-org/gomatrixserverlib#411

Spec Clarifications

• Document why /state_ids can respond with a 404. (#1521)
  • We already 404 if we can't find the event

Room Versions

Backwards Compatible Changes

• Add room version 11 as per MSC3820.
  • Move redacts from top level to content on m.room.redaction events in room version 11, as per MSC2174.
  • Remove creator from m.room.creator events in room version 11, as per MSC2175.
  • Remove remaining usage of origin from events in room version 11, as per MSC3989.
  • Update the redaction rules in room version 11, as per MSC2176 and MSC3821.

Appendices

Backwards Compatible Changes

• Allow + in Matrix IDs, as per MSC4009.