Migrate touch_firmware_versions.py to Python 3

BUG=chromium:1031760
TEST=python3 touch_firmware_versions.py

Change-Id: I834273e8259b04e119f261791c1dae637546bb2f
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crostestutils/+/1959073
Tested-by: Greg Edelston <gredelston@google.com>
Reviewed-by: Katherine Threlkeld <kathrelkeld@chromium.org>
Reviewed-by: Aviv Keshet <akeshet@chromium.org>
Commit-Queue: Greg Edelston <gredelston@google.com>
1 file changed