[PrivacyBadger] Privacy Badger 2017.3.23 Firefox-only release

[Alexei]

Hi all,

We have released Privacy Badger version 2017.3.23. This is a
Firefox-only critical bug fix release. Please be sure to update, as
previous versions of Privacy Badger on Firefox will no longer learn from
cookie tracking in Firefox 52 and up.

For further details, please consult our release notes on GitHub:
https://github.com/EFForg/privacybadger/releases/tag/release-2017.3.22