Release 16.12.0

[jeddy3]

• stylelint-ecosystem-tester check
• stylelint release
• stylelint-config-recommended update/release
• stylelint-config-standard update/release
• stylelint.io update
• stylelint-demo check
• tweet

We've got a couple of additions and a few fixes to go out. I'll likely have time to do a release this weekend.

[Mouvedia]

Should we wait for @stylistic/stylelint-plugin to address stylelint/stylelint-ecosystem-tester#62 before releasing?

[jeddy3]

I think we're fine to release.

[jeddy3]

Starting the release.

[jeddy3]

Done 🎉. Thank you to everyone who contributed to this release!