Updated tk-multi-loader2 to v1.20.0

Release notes: https://github.com/shotgunsoftware/tk-multi-loader2/wiki/Release-Notes#v1200

Author: jfboismenu

env/includes/common/apps.yml

@@ -45,7 +45,7 @@ common.apps.tk-multi-publish2.location:
 common.apps.tk-multi-loader2.location:
   type: app_store
   name: tk-multi-loader2
-  version: v1.12.0
+  version: v1.20.0
 
 common.apps.tk-multi-shotgunpanel.location:
   type: app_store