Update PRESUBMIT.cfg to include checks for release_notes.

BUG=b/173034990
TEST=manually checking on some changelists.
RELEASE_NOTE=None

Change-Id: I5bc36bb524a3f32a29685dc2a5857b276e87708d
Reviewed-on: https://cos-review.googlesource.com/c/third_party/overlays/portage-stable/+/8580
Reviewed-by: Dexter Rivera <riverade@google.com>
Tested-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
1 file changed