chg: [drone] update version of drone

Warning, ``docker.0k.io/drone:1.1`` is ``drone:1.0``.

drone/metadata.yml

@@ -1,7 +1,7 @@
 description: "Drone Server"
 maintainer: "Valentin Lab <valentin.lab@kalysto.org>"
 ## XXXvlab: docker uses the 'build' directory or the 'image:' option here.
-docker-image: docker.0k.io/drone:1.0
+docker-image: docker.0k.io/drone:1.1
 docker-compose:
   environment:
     DRONE_OPEN: "true"  ## users are authenticated through the vcs-manager anyway