format: python: clean up file header a bit

Since black seems to completely ignore (for the most part) the top
of the file, clean it up ourselves a bit.

BUG=None
TEST=CQ passes

Change-Id: I6b0b5aea970a0ac625317d51c0f7f77cc6d4121a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/4219954
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Nicholas Bishop <nicholasbishop@google.com>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
diff --git a/api/controller/dependency_unittest.py b/api/controller/dependency_unittest.py
index 5d17d73..acd0370 100644
--- a/api/controller/dependency_unittest.py
+++ b/api/controller/dependency_unittest.py
@@ -1,6 +1,7 @@
 # Copyright 2019 The ChromiumOS Authors
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
+
 """Board build dependency service tests."""
 
 import os