Moving charms to use latest stable release container image

Change-Id: I92897515d7c8843bb619080cecee3b3c2aedb976
Signed-off-by: sousaedu <eduardo.sousa@canonical.com>
diff --git a/installers/charm/pla/config.yaml b/installers/charm/pla/config.yaml
index f3318fc..57c5df0 100644
--- a/installers/charm/pla/config.yaml
+++ b/installers/charm/pla/config.yaml
@@ -19,7 +19,7 @@
   image:
     description: Docker image name
     type: string
-    default: opensourcemano/pla:8
+    default: opensourcemano/pla:latest
   image_username:
     description: Docker repository username
     type: string