V3.12.3: a security release (with working xqueue)

Hi all! We just released Tutor v3.12.3 which contains a security patch for edx-platform. See the relevant discussion on the Open edX forums. All users are strongly encouraged to upgrade!

We also released v0.2.0 of the Xqueue plugin: this includes major changes – some of them will actually make the plugin work :sweat_smile:

As usual, your feedback will be appreciated!