Update chart dependency for postgresql

* Update Chart.yaml

Set postgresql Chart version to 12.1.6. Bitnami deleted 11.1.3.

* Force postgresql image tag version

Co-authored-by: Émilien Devos <contact@emiliendevos.be>

kubernetes/values.yaml

@@ -34,6 +34,8 @@ securityContext:
 
 # See https://github.com/bitnami/charts/tree/master/bitnami/postgresql
 postgresql:
+  image:
+    tag: 13
   auth:
     username: kemal
     password: kemal