[stable/ghost] Release 2.1.16 (#4137)

* ghost: update to `bitnami/ghost:1.21.5-r0`

* ghost: bump chart appVersion to `1.21.5`

* ghost: bump chart version to `2.1.16`

stable/ghost/Chart.yaml

@@ -1,6 +1,6 @@
 name: ghost
-version: 2.1.15
-appVersion: 1.21.4
+version: 2.1.16
+appVersion: 1.21.5
 description: A simple, powerful publishing platform that allows you to share your
   stories with the world
 keywords:

stable/ghost/values.yaml

@@ -1,7 +1,7 @@
 ## Bitnami Ghost image version
 ## ref: https://hub.docker.com/r/bitnami/ghost/tags/
 ##
-image: bitnami/ghost:1.21.4-r0
+image: bitnami/ghost:1.21.5-r0
 
 ## Busybox image used to configure volume permissions
 ##