Release v3.1.2 (mdn#9272)

* Increment version number

* Start release notes for v3.1.2

* Add stats

* Fix compare link formatting

Weekly data release for 2021-02-18

Weekly data release for 2021-02-11

Weekly data release for 2021-02-04

Weekly data release for 2021-01-28

Weekly data release for 2021-01-21

Weekly data release for 2021-01-14

Weekly data release for 2021-01-07

Weekly data release for 2020-12-17

3.0.0