Update dependencies to enable easy single-tag deployments

Previously every deployment (even just for a single tag, such as
`ansible-playbook site.yml --tags landingpage`) would have the caddy
deployment in its dependency.

That meant in effect whenever there was an updated caddy image, the role
would update it and we would lose all previous caddy configuration -
which in turn would necessitate a complete redeploymnet of all steps.
This is now not the case anymore.

roles/monica/meta/main.yml

@@ -4,11 +4,10 @@ galaxy_info:
   author: Marty Oehme
   description: Installs monica as a docker stack service
   license: GPL-3.0-only
-  min_ansible_version: 2.9
+  min_ansible_version: "2.9"
   galaxy_tags: []
 
 
 dependencies:
-  - docker
   - docker-swarm
-  - caddy
+  - caddy_id