helm: bump chart and default image version to 3.1.5 (#14256)

chart/Chart.yaml

@@ -20,7 +20,7 @@ version: 0.1.0
 # This is the version number of the application being deployed. This version number should be
 # incremented each time you make changes to the application. Versions are not expected to
 # follow Semantic Versioning. They should reflect the version the application is using.
-appVersion: 3.1.4
+appVersion: 3.1.5
 
 dependencies:
   - name: elasticsearch

chart/values.yaml.template

@@ -4,7 +4,7 @@ image:
   repository: tootsuite/mastodon
   pullPolicy: Always
   # https://hub.docker.com/r/tootsuite/mastodon/tags
-  tag: v3.1.4
+  tag: v3.1.5
   # alternatively, use `latest` for the latest release or `edge` for the image
   # built from the most recent commit
   #