[Engineering] [Breaking Change] Scap3 stage changes will break custom checks

[Tyler Cipriani]

This is a change that affects services that have moved to deployment
via Scap3 (not MediaWiki deployments).

The 3.2.0-1 release that is currently live makes an important change
to the stages in which custom checks may be run. There is now a new
stage called `restart_service` that occurs after the `promote` stage.
The `promote` stage no longer does a service restart. This change is
outlined in the Scap3 docs[0].

This change likely means that you need to move any custom checks (in
scap/checks.yaml) that were intended to run post-service restart to
use the stage `restart_service` rather than `promote`.

For example this check, which depends on a service restart to work correctly:

  checks:
    service_responds:
      type: command
      stage: promote
      command: curl -Ss localhost:1234

Should now be written as:

  checks:
    service_responds:
      type: command
      stage: restart_service
      command: curl -Ss localhost:1234

Sorry for any inconvenience. For future releases, changelog highlights
will be sent to the list prior to release.

-- Tyler

[0]. https://doc.wikimedia.org/mw-tools-scap/scap3/quickstart/setup.html#service-restarts-and-checks