Add upgrade-instagram-poster to workflow branches

Author: danielbusnz

.github/workflows/rescuegroups-api.yml

@@ -4,7 +4,7 @@ on:
   push:
     # We are doing this for testing purposes, but when we start posting, we should remove this line
     branches:
-      [master]
+      [master, upgrade-instagram-poster]
   workflow_dispatch:
   schedule:
     # Every 4 hours