Update changelog

Author: adamwathan

CHANGELOG.md

@@ -9,6 +9,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Nothing yet!
 
+## [2.0.0-alpha.18] - 2020-11-13
+
+### Changed
+
+- `black` and `white` have been added to `colors.js` ([b3ed724](https://github.com/tailwindlabs/tailwindcss/commit/b3ed724))
+
+### Fixed
+
+- Add support for colors as closures to `ringColor` and `ringOffsetColor`, previously would crash build ([62a47f9](https://github.com/tailwindlabs/tailwindcss/commit/62a47f9))
+
 ## [2.0.0-alpha.17] - 2020-11-13
 
 ### Changed
@@ -1182,7 +1192,8 @@ No release notes
 
 - Everything!
 
-[unreleased]: https://github.com/tailwindlabs/tailwindcss/compare/v2.0.0-alpha.17...HEAD
+[unreleased]: https://github.com/tailwindlabs/tailwindcss/compare/v2.0.0-alpha.18...HEAD
+[2.0.0-alpha.18]: https://github.com/tailwindlabs/tailwindcss/compare/v2.0.0-alpha.17...v2.0.0-alpha.18
 [2.0.0-alpha.17]: https://github.com/tailwindlabs/tailwindcss/compare/v2.0.0-alpha.16...v2.0.0-alpha.17
 [2.0.0-alpha.16]: https://github.com/tailwindlabs/tailwindcss/compare/v2.0.0-alpha.15...v2.0.0-alpha.16
 [2.0.0-alpha.15]: https://github.com/tailwindlabs/tailwindcss/compare/v2.0.0-alpha.14...v2.0.0-alpha.15