See matrix-org/matrix-doc#3720

Co-authored-by: Sean Quah <8349537+squahtx@users.noreply.github.com>

* Remove `trial` section from setup.cfg

This was added in the initial commit from 2014. I can't see that it does
anything. Maybe it's there so that you can run `trial` without any extra
args, but if I do that then I just get the `--help` message.

* Move flake8's config to its own file

... to ensure it gets a proper log context, mostly.

Fix slow performance of `/logout` in some cases where refresh tokens are in use. The slowness existed since the initial implementation of refresh tokens. (#12056)

This is an endpoint that we have server-side support for, but no client-side support. It's going to be useful for resyncing partial-stated rooms, so let's introduce it.

By including "bot" in the User-Agent, which some sites use
to decide whether to include additional Open Graph information.

* Don't build distribution pkgs in tests.yml
* Run `release-artifacts` on release branches
* Use backend-meta workflow for packaging

A follow-up to #12005, in which I apparently missed that there are a bunch of other places that assume the create event is in the auth chain.

These started failing in
https://github.com/matrix-org/synapse/pull/12031... I'm a bit mystified by how
they ever worked.

Co-authored-by: Patrick Cloke <patrickc@matrix.org>

Since it is reasonable to give a future or past auth provider,
which might not be in the current configuration.

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

Upgrade mypy to 0.931, mypy-zope to 0.3.5 and fix new complaints.

Keeping backwards compatibility with the unstable flag for now.

Fix 500 error with Postgres when looking backwards with the MSC3030 `/timestamp_to_event` endpoint (#12024)

Fixes #11962

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

Part of my work on #11249: add code to handle the new fields added in MSC3706.

As the comment says, virtualenv is a pile of fail.

msc3706 proposes changing the `/send_join` response:

> Any events returned within `state` can be omitted from `auth_chain`.

Currently, we rely on `m.room.create` being returned in `auth_chain`, but since
the `m.room.create` event must necessarily be part of the state, the above
change will break this.

In short, let's look for `m.room.create` in `state` rather than `auth_chain`.

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>