This may be a bit premature, because the bridge didn't work for me
the last time I tried it (RC3).

Some bugs have been fixed to make our config compatible with v1.0.0
though, so it may work for some people (especially those starting
fresh).

I'm not for shipping potentially broken things, but given that we were
using `docker.io/halfshot/matrix-appservice-discord:latest` and that
points to v1.0.0 already (with no other tag we can use), our setup was
already broken in any case.

Now, at least it has some chance of running.