Add parent_role in targets.delegate

Signed-off-by: marinamoore <[email protected]>

Author: mnm678

tuf/repository_tool.py

@@ -2412,7 +2412,8 @@ def delegate(self, rolename, public_keys, paths, threshold=1,
                 'keyids': keyids,
                 'threshold': threshold,
                 'terminating': terminating,
-                'paths': list(relative_targetpaths.keys())}
+                'paths': list(relative_targetpaths.keys()),
+                'parent_role' : self._rolename}
 
     if paths:
       roleinfo['paths'] = paths