Bump kolla to stackhpc/18.6.0.2

Author: bbezak

etc/kayobe/stackhpc.yml

@@ -153,7 +153,7 @@ stackhpc_repo_elrepo_9_version: "{{ stackhpc_repo_distribution }}"
 
 # Kolla source repository.
 stackhpc_kolla_source_url: "https://github.com/stackhpc/kolla"
-stackhpc_kolla_source_version: stackhpc/18.5.0.2
+stackhpc_kolla_source_version: stackhpc/18.6.0.2
 
 # Kolla Ansible source repository.
 stackhpc_kolla_ansible_source_url: "https://github.com/stackhpc/kolla-ansible"