bump to 2018.8.0

Change-Id: Ia767f61c6d08168726cd91b8f622c0feb6e2c345
diff --git a/classes/cluster/mcp-offline/infra/init.yml b/classes/cluster/mcp-offline/infra/init.yml
index ac014c8..9473f52 100644
--- a/classes/cluster/mcp-offline/infra/init.yml
+++ b/classes/cluster/mcp-offline/infra/init.yml
@@ -7,7 +7,8 @@
     # Don't set it "false" before you configure sudo policies and enable power users.
     # linux_system_user_sudo: true
     docker_compose_image: apt:5000/compose:1.8.0
-    apt_mk_version: "proposed"
+    #apt_mk_version: "proposed"
+    apt_mk_version: "2018.8.0"
     aptly_server_hostname: apt
     aptly_server_address: 127.0.0.1
     linux_repo_refresh_db: true