Add Pyup comment to requirements.txt
Add Pyup comment to requirements.txt

This matches what’s in requirements.in, but the Pyup comments don’t
automatically get copied when generating requirements.txt. This causes
Pyup’s safety CI to complain we’re using a version with a known
vulnerability (which doesn’t affect us since we don’t use websockets).

alphagov/notifications-admin,alphagov/notifications-admin,alphagov/notifications-admin,alphagov/notifications-admin