[stable/ghost] Release 3.1.5 (#5816)

* ghost: update to `1.23.1`

* ghost: bump chart appVersion to `1.23.1`

* ghost: bump chart version to `3.1.5`

stable/ghost/Chart.yaml

@@ -1,6 +1,6 @@
 name: ghost
-version: 3.1.4
-appVersion: 1.23.0
+version: 3.1.5
+appVersion: 1.23.1
 description: A simple, powerful publishing platform that allows you to share your
   stories with the world
 keywords:

stable/ghost/values.yaml

@@ -4,7 +4,7 @@
 image:
   registry: docker.io
   repository: bitnami/ghost
-  tag: 1.23.0
+  tag: 1.23.1
   ## Specify a imagePullPolicy
   ## Defaults to 'Always' if image tag is 'latest', else set to 'IfNotPresent'
   ## ref: http://kubernetes.io/docs/user-guide/images/#pre-pulling-images