Merge pull request #419 from robintown/ec-deployment

Use Element Call's staging deployment for nightly

element.io/nightly/config.json

@@ -49,5 +49,8 @@
         "feature_spotlight": true,
         "feature_video_rooms": true
     },
+    "element_call": {
+        "url": "https://element-call.netlify.app"
+    },
     "map_style_url": "https://api.maptiler.com/maps/streets/style.json?key=fU3vlMsMn4Jb6dnEIFsx"
 }