Remove space between 'web hook' in title

Author: Jamin Wong

docker-hub/builds/classic.md

@@ -39,7 +39,7 @@ Likewise, you can switch back to new Automated Build by clicking on this link at
 
 
 
-## Adding Github web hook manually
+## Adding Github webhook manually
 
 A GitHub webhook allows GitHub to notify Docker Hub when something has
 been committed to a given Git repository.