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/mon/metadata.yaml b/installers/charm/mon/metadata.yaml
index 2578b1e..05aa547 100644
--- a/installers/charm/mon/metadata.yaml
+++ b/installers/charm/mon/metadata.yaml
@@ -37,7 +37,7 @@
   image:
     type: oci-image
     description: OSM docker image for MON
-    upstream-source: "opensourcemano/mon:8"
+    upstream-source: "opensourcemano/mon:latest"
 requires:
   kafka:
     interface: kafka