V1.0!

Cutting a release so there's an official v1 out there. Mage is fully usable and stable at this point. More features will always be filtering in, and we'll cut new releases for those as well.

The docs at https://magefile.org are always up to date with the head of master. If new releases have come out since v1, and you want to reference the docs specifically for v1 on the website, just go to https://v1.magefile.org.