Updated tk-multi-shotgunpanel to v1.8.4

Release notes: https://github.com/shotgunsoftware/tk-multi-shotgunpanel/wiki/Release-Notes#v184

Author: Toolkitty

env/includes/common/apps.yml

@@ -43,7 +43,7 @@ common.apps.tk-multi-loader2.location:
 common.apps.tk-multi-shotgunpanel.location:
   type: app_store
   name: tk-multi-shotgunpanel
-  version: v1.8.3
+  version: v1.8.4
 common.apps.tk-multi-launchapp.location:
   type: app_store
   name: tk-multi-launchapp