Snack case as requested in gitpython-developers#903

Author: Arthur-Milchior

git/repo/base.py

@@ -1063,7 +1063,7 @@ def has_separate_working_tree(self):
     def __repr__(self):
         return '<git.Repo "%s">' % self.git_dir
 
-    def currentlyRebasingOn(self):
+    def currently_rebasing_on(self):
         """
         :return: The hash of the commit which is currently being replayed while rebasing.