Update requirements.yml to be installable without force flag

Due to galaxy verification on versions, we can't install requirements
without --force when we set an FQCN name instead of git path.

This causes ansible-lint to fail with:
Non integer values in LooseVersion ('master')

Change intends to fix this and ensure requirements are more
easily installable.

Change-Id: Ia950023d3d747e9fff4c900b207ce7087c4e7314

molecule/default/molecule.yml

@@ -3,7 +3,6 @@ dependency:
   name: galaxy
   options:
     requirements-file: requirements.yml
-    force: true
 
 driver:
   name: docker

requirements.yml

@@ -1,6 +1,5 @@
 ---
 collections:
-  - name: openstack.config_template
-    source: https://opendev.org/openstack/ansible-config_template
+  - name: https://opendev.org/openstack/ansible-config_template
     type: git
     version: master