Update CHANGELOG and release version 0.15.16

CHANGELOG.md

 # Changelog
 
+## [0.15.16] - 2023-09-06
+
+* Update nextcloud helm chart to v3.5.22
+  - In particular, this upgrades Nextcloud to 27.0.2
+* Update onlyoffice app to 8.2.0.
+* Reduce output of app install/upgrade script, by removing the tar output
+  listing all app files.
+
 ## [0.15.15] - 2023-08-02
 
 * Run our configuration and app install/update scripts on chart install and

Chart.yaml

@@ -3,8 +3,8 @@ apiVersion: v2
 description: |
   A helm chart for installing NextCloud and setting up ONLYOFFICE integration
 name: nextcloud-onlyoffice
-appVersion: NC-26.0.2-OO-7.2.2.56
-version: 0.15.15
+appVersion: NC-27.0.2-OO-7.2.2.56
+version: 0.15.16
 icon: https://cdn.rawgit.com/docker-library/docs/defa5ffc7123177acd60ddef6e16bddf694cc35f/nextcloud/logo.svg
 dependencies:
   # https://artifacthub.io/packages/helm/nextcloud/nextcloud