[ANN] You can now sign in to MDN with your GitHub account

[Maris Fogels]

Hi everyone,

You can now sign into to MDN using your GitHub account in addition to
using Mozilla Persona.

You can also associate an existing MDN account with GitHub. To do so,
sign in to MDN and visit the account connections page:
https://developer.mozilla.org/users/account/connections. You can also
access the Account connections page from your profile page.

Please file a bug under 'Account Help' in the MDN bug tracker if you
encounter an issue while signing in:
https://bugzilla.mozilla.org/enter_bug.cgi?format=__standard__&product=Mozilla%20Developer%20Network

Enjoy,

-mars