Bump K-A to 18.8.0.7 to fix A-C-K install

Author: seunghun1ee

etc/kayobe/stackhpc.yml

@@ -176,7 +176,7 @@ stackhpc_kolla_source_version: stackhpc/18.8.0.5
 
 # Kolla Ansible source repository.
 stackhpc_kolla_ansible_source_url: "https://github.com/stackhpc/kolla-ansible"
-stackhpc_kolla_ansible_source_version: stackhpc/18.8.0.6
+stackhpc_kolla_ansible_source_version: stackhpc/18.8.0.7
 
 ###############################################################################
 # Container image registry