Warn users when sourcegraph becomes out of date
Created by: daxmc99
Addresses: https://github.com/sourcegraph/sourcegraph/issues/9708
This PR warns users when sourcegraph is out of date and supports offline alerting. The alerts will become more severe as the instance becomes further out of date.
Still in progress:
-
Adding tests -
Confirming UI changes are what we expect (increasing severity colors + animations) -
Users are only notified when Sourcegraph is >4 months out of date. - Can be disabled via env var
DISABLE_SECURITY_NOTICES=true