Activate github builds

photoprism/config.json

@@ -45,6 +45,7 @@
     "working_dir": "/data/photoprism"
   },
   "homeassistant": "0.92.0b2",
+  "image": "ghcr.io/alexbelgium/photoprism-{arch}",
   "ingress": true,
   "ingress_stream": true,
   "map": [
@@ -99,4 +100,4 @@
   "slug": "photoprism",
   "url": "https://github.com/alexbelgium/hassio-addons-test",
   "version": "20220121-2"
-}
+}