Update hash of regional_worklow with the latest (#147)

Externals.cfg

@@ -3,7 +3,7 @@ protocol = git
 repo_url = https://github.com/NOAA-EMC/regional_workflow
 # Specify either a branch name or a hash but not both.
 #branch = develop
-hash = 40cfeff
+hash = 5bbbc53
 local_path = regional_workflow
 required = True