r/frigate: Update to v0.15

Frigate has evolved a lot over the past year or so since v0.13.
Notably, some of the configuration options have been renamed, and
_events_ have become _alerts_ and _detections_.  There's also now
support for authenication, though we don't need it because we're using
Authelia.

roles/frigate/tasks/main.yml

@@ -37,7 +37,7 @@
     path: /var/lib/frigate/tmp
     owner: frigate
     group: frigate
-    mode: '0700'
+    mode: u=rwx,go=rx
     state: directory
   tags:
   - datadir