Upgrade the appversion comment

Functionally this comment achieves nothing but it makes it easier to see
what version of the app is deployed as opposed to just the chart
version.

main.tf

@@ -4,7 +4,7 @@ resource "helm_release" "external-dns" {
   repository = "https://charts.bitnami.com/bitnami"
   chart      = "external-dns"
   version    = "6.5.6"
-  # appVersion: 0.7.6
+  # appVersion: 0.12.0
 
   values = [
     templatefile(