add compose-utils to bodhi-backend<foo>

in order to stage the release we need top have compose-utils installed
we use the compose-partial-copy script to do teh syncing.The box of
choice for staging is bodhi-backend do to the readily available sigul
setup so we can sign the CHECKSUM files.
https://pagure.io/releng/blob/master/f/scripts/stage-release.sh is the
script used to stage the release.

Signed-off-by: Dennis Gilmore <ausil@fedoraproject.org>

roles/bodhi2/backend/tasks/main.yml

@@ -25,6 +25,7 @@
   - python-alembic
   - python-scandir
   - python2-productmd
+  - compose-utils
   tags:
   - packages
   - bodhi