Merge pull request swiftlang#40133 from jorng/update-checkout_py3

update-checkout: Explicitly use python3

Author: jorng

utils/update-checkout

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import sys
 

utils/update_checkout/run_tests.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 # This source file is part of the Swift.org open source project
 #
@@ -13,9 +13,6 @@
 Small script used to easily run the update_checkout module unit tests.
 """
 
-
-from __future__ import absolute_import, unicode_literals
-
 import os
 import shutil
 import sys

utils/update_checkout/update_checkout/update_checkout.py

@@ -8,8 +8,6 @@
 # See https://swift.org/LICENSE.txt for license information
 # See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-from __future__ import print_function
-
 import argparse
 import json
 import os