scripts: convert random standalone programs to python3 only

Nothing imports these, so should be safe to convert.

BUG=chromium:997354
TEST=CQ passes

Change-Id: Ic0ddd990c7bb78a020990a9cff01ae2a27f29e1a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2066684
Reviewed-by: Alex Klein <saklein@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/cros_generate_tidy_warnings.py b/scripts/cros_generate_tidy_warnings.py
index ea466e8..34d4995 100644
--- a/scripts/cros_generate_tidy_warnings.py
+++ b/scripts/cros_generate_tidy_warnings.py
@@ -9,12 +9,17 @@
 
 import os
 import shutil
+import sys
 
 from chromite.lib import cros_build_lib
 from chromite.lib import commandline
 from chromite.lib import osutils
 from chromite.lib import sudo
 
+
+assert sys.version_info >= (3, 6), 'This module requires Python 3.6+'
+
+
 DEFAULT_NAME = 'clang_tidy_warnings.tar.xz'
 TIDY_WARNINGS = 'clang_tidy_warnings'
 PARSING_SCRIPT = ('/mnt/host/source/src/third_party/toolchain-utils/'