See compose-spec/compose-go#325 for the acutal spec change. This
propagates it to the Engine API object and adds an E2E test via
Cucumber 🥒Fixes#9873.
Signed-off-by: Milas Bowman <milas.bowman@docker.com>
Evidently `ping` doesn't respond to `SIGTERM`, so use `init` to
get Tini supervising it. This changes the exit code to 143 since
it's not hitting the 10s timeout and getting a `SIGKILL` (137).
Signed-off-by: Milas Bowman <milas.bowman@docker.com>