Update hashbangs to python3 am: 54a6f9175a

Original change: https://android-review.googlesource.com/c/platform/prebuilts/checkstyle/+/1873797

Change-Id: Ice55c515ed2bbbd825b6e83801b122046f812433
diff --git a/checkstyle.py b/checkstyle.py
index be3b7f0..df5d5fc 100755
--- a/checkstyle.py
+++ b/checkstyle.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 #
 # Copyright 2015, The Android Open Source Project
diff --git a/tests.py b/tests.py
index 75f66c8..0e7dd1f 100755
--- a/tests.py
+++ b/tests.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 #
 # Copyright 2015, The Android Open Source Project