remove redundant inner header from delegate authors section

Summary:
as Title

Created from CodeHub with https://fburl.com/edit-in-codehub

Reviewed By: kirklandsign

Differential Revision: D49514413

fbshipit-source-id: 92444344d428a22450971a0a27467c8a70aa5ac1

Author: digantdesai

CONTRIBUTING.md

@@ -112,8 +112,6 @@ must work with threading**
 
 ## For Delegate Authors
 
-### Dependencies Management for a Delegate
-
 * Use [this](/docs/website/docs/contributors/delegates.md)
 guide when integrating your delegate with Executorch.