Use the exec Bash command so that the final running application becomes
the container’s PID 1. This allows the application to receive any Unix
signals sent to the container, in accordance with
https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#entrypoint
Currently, SIGTERM signals sent by kubernetes are not passed to the
executed binary.
Signed-off-by: Xavier Duthil <xavier.duthil@corp.ovh.com>