This brings Dendrite's appservice spec support up to v1.4, from the
previous level of pre-release-spec support only (even r0.1.0 wasn't
supported for pushing transactions 🙃). There are config options to
revert to the old behavior, but the default is v1.4+ only. [Synapse also
does
that](https://element-hq.github.io/synapse/latest/usage/configuration/config_documentation.html#use_appservice_legacy_authorization)
mautrix bridges will drop support for legacy paths and authentication
soon (and possibly also require matrix v1.4 to be advertised, but I
might add some workaround to not require that for dendrite)
Signed-off-by: Tulir Asokan <tulir@maunium.net>
0f6b81f456