Since the :post_started_at and :post_ended_at fields are of type Date, we check
with Date.current and not with Time.current.
This change has been caused because some test suites were failing
(https://github.com/consul/consul/runs/2170798218?check_suite_focus=true).
The code we had was causing the banners to be available a few hours earlier
or later than they should be depending on the time zone of the application.