[HTTPS-Everywhere] Upcoming 5.0.8 release

[Jacob Hoffman-Andrews]

I'm preparing for a 5.0.8 release later today or tomorrow. Please let me
know if there is something urgent that needs to get in before then.

With the 5.0.8 release I'll be making another attempt to get Mozilla's
signing infrastructure to work for us
(https://github.com/EFForg/https-everywhere/issues/2051), so the
"unsigned add-on" warnings should go away.