Downgrade Nextcloud chart

Because of https://github.com/nextcloud/helm/issues/296 I had to
downgrade the chart version to 3.1.2. This is fine, because 3.2.0
doesn't upgrade Nextcloud server, it just adds some bugs

Chart.yaml

@@ -9,7 +9,7 @@ icon: https://cdn.rawgit.com/docker-library/docs/defa5ffc7123177acd60ddef6e16bdd
 dependencies:
   # https://artifacthub.io/packages/helm/nextcloud/nextcloud
   - name: nextcloud
-    version: 3.2.0
+    version: 3.1.2
     repository: "https://nextcloud.github.io/helm"
   # https://artifacthub.io/packages/helm/bitnami/rabbitmq
   - name: rabbitmq