obmc-gerrit: disable python caching

Set the `-B` option to Python to disable caching.  This prevents
it from polluting the repository with cache files.  Since this
script isn't used in performance critical paths, this seems
reasonable.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I1f935129f2abc0e1bc1211f6e21e6ead385ae9a5
diff --git a/maintainers/obmc-gerrit b/maintainers/obmc-gerrit
index f285f61..fae6725 100755
--- a/maintainers/obmc-gerrit
+++ b/maintainers/obmc-gerrit
@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env -S python3 -B
 #
 # SPDX-License-Identifier: Apache-2.0
 # Copyright (C) 2018 IBM Corp.