Log Message:
Update to 0.12.1

Changelog:
0.12.1
Bug Fixes
    Re-introduce Ruby 2.3 support and test Jekyll 3.7+ (#272)

0.12.0
    Allow Jekyll v4 (still alpha)

Development Fixes
    style: fix offenses in specs (#248)
    dev: update CI and style settings (#258)
    Enable testing for Windows platform (#265)