Update changelog

Author: adamwathan

CHANGELOG.md

@@ -9,6 +9,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Nothing yet!
 
+## [2.0.0-alpha.20] - 2020-11-13
+
+### Changed
+
+- Remove `clearfix` utility, recommend `flow-root` instead ([#2766](https://github.com/tailwindlabs/tailwindcss/pull/2766))
+
 ## [2.0.0-alpha.19] - 2020-11-13
 
 ### Fixed
@@ -1198,7 +1204,8 @@ No release notes
 
 - Everything!
 
-[unreleased]: https://github.com/tailwindlabs/tailwindcss/compare/v2.0.0-alpha.19...HEAD
+[unreleased]: https://github.com/tailwindlabs/tailwindcss/compare/v2.0.0-alpha.20...HEAD
+[2.0.0-alpha.20]: https://github.com/tailwindlabs/tailwindcss/compare/v2.0.0-alpha.19...v2.0.0-alpha.20
 [2.0.0-alpha.19]: https://github.com/tailwindlabs/tailwindcss/compare/v2.0.0-alpha.18...v2.0.0-alpha.19
 [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