Update parameter name to repository_slug (#959)

Author: MSumulong

docs/bitbucket.rst

@@ -257,13 +257,13 @@ Branch permissions
 .. code-block:: python
 
     # Set branches permissions
-    bitbucket.set_branches_permissions(project_key, multiple_permissions=False, matcher_type=None, matcher_value=None, permission_type=None, repository=None, except_users=[], except_groups=[], except_access_keys=[], start=0, limit=25)
+    bitbucket.set_branches_permissions(project_key, multiple_permissions=False, matcher_type=None, matcher_value=None, permission_type=None, repository_slug=None, except_users=[], except_groups=[], except_access_keys=[], start=0, limit=25)
 
     # Delete a single branch permission by permission id
-    bitbucket.delete_branch_permission(project_key, permission_id, repository=None)
+    bitbucket.delete_branch_permission(project_key, permission_id, repository_slug=None)
 
     # Get a single branch permission by permission id
-    bitbucket.get_branch_permission(project_key, permission_id, repository=None)
+    bitbucket.get_branch_permission(project_key, permission_id, repository_slug=None)
 
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