Updated tk-shell to v0.9.1

Release notes: https://github.com/shotgunsoftware/tk-shell/wiki/Release-Notes#v091

Author: Toolkitty

env/includes/common/engines.yml

@@ -63,7 +63,7 @@ common.engines.tk-desktop2.location:
 common.engines.tk-shell.location:
   type: app_store
   name: tk-shell
-  version: v0.9.0
+  version: v0.9.1
 common.engines.tk-shotgun.location:
   type: app_store
   name: tk-shotgun