paygen: Correct paygen_payload_lib.GenerateUpdatePayload() signature

I didn't update all callers. These apparently don't have any test
coverage.

BUG=b:265885353
TEST=./run_tests
TEST=`cros lint $(git grep -l paygen)`

Change-Id: I17c0cd76a6e545b8f624c82fd0b8f91fdf0feb0b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/4652228
Auto-Submit: Brian Norris <briannorris@chromium.org>
Commit-Queue: Brian Norris <briannorris@chromium.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
diff --git a/scripts/cros_generate_update_payload_unittest.py b/scripts/cros_generate_update_payload_unittest.py
index ac6ea02..b49fd54 100644
--- a/scripts/cros_generate_update_payload_unittest.py
+++ b/scripts/cros_generate_update_payload_unittest.py
@@ -4,6 +4,7 @@
 
 """Unit tests for cros_generate_update_payload."""
 
+from chromite.lib import chroot_lib
 from chromite.lib import cros_test_lib
 from chromite.lib import partial_mock
 from chromite.lib.paygen import paygen_payload_lib
@@ -41,6 +42,7 @@
         )
 
         paygen_mock.assert_called_once_with(
+            chroot_lib.Chroot(),
             partial_mock.HasString("foo-tgt-image"),
             partial_mock.HasString("foo-output"),
             src_image=partial_mock.HasString("foo-src-image"),