Clean up relay credentials generation

[chadwhitacre]

This is a follow-up to #1273, and it should get CI back on track on master.

[chadwhitacre]

@aminvakil It looks like there is no --no-tty option in Docker Compose 1, only in 2. That could explain why merging #1251 caused CI to start failing.

$ docker-compose run -T --no-deps relay credentials show      
Creating sentry-self-hosted_relay_run ... done
Credentials:
  relay id: ed128877-ceb6-47e0-8a4e-e3df4bed162f
  public key: EyGAkE-3wBlBQuSbKJLsXdhQWEMsaZIDSnOCvnVE5zo
$
$
$ docker-compose run --no-tty --no-deps relay credentials show
Run a one-off command on a service.

For example:

    $ docker-compose run web python manage.py shell

By default, linked services will be started, unless they are already
running. If you do not want to start linked services, use
`docker-compose run --no-deps SERVICE COMMAND [ARGS...]`.

Usage:
    run [options] [-v VOLUME...] [-p PORT...] [-e KEY=VAL...] [-l KEY=VALUE...] [--]
        SERVICE [COMMAND] [ARGS...]

Options:
    -d, --detach          Detached mode: Run container in the background, print
                          new container name.
    --name NAME           Assign a name to the container
    --entrypoint CMD      Override the entrypoint of the image.
    -e KEY=VAL            Set an environment variable (can be used multiple times)
    -l, --label KEY=VAL   Add or override a label (can be used multiple times)
    -u, --user=""         Run as specified username or uid
    --no-deps             Don't start linked services.
    --rm                  Remove container after run. Ignored in detached mode.
    -p, --publish=[]      Publish a container's port(s) to the host
    --service-ports       Run command with the service's ports enabled and mapped
                          to the host.
    --use-aliases         Use the service's network aliases in the network(s) the
                          container connects to.
    -v, --volume=[]       Bind mount a volume (default [])
    -T                    Disable pseudo-tty allocation. By default `docker-compose run`
                          allocates a TTY.
    -w, --workdir=""      Working directory inside the container
$
$
$ docker-compose --version
docker-compose version 1.29.2, build 5becea4c
$

[chadwhitacre]

Bah ... but in that case why was CI green on #1251? 🤔

[chadwhitacre]

Hrm, red CI ... 🧐

[chadwhitacre]

I reticketed the CI flakiness as #1293. Rebased here and aiming to merge ...