Update CHANGELOG.md

Author: morgante

CHANGELOG.md

@@ -11,10 +11,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 * Allow 3.x google provider ([#77](https://www.github.com/terraform-google-modules/terraform-google-lb-http/issues/77)) ([650d639](https://www.github.com/terraform-google-modules/terraform-google-lb-http/commit/650d639beba895dabbaeb312090d013fde9a68bd))
 
-## [Unreleased]
-### Changed
-- Add support for google provider version 3.x [#77]
-
 ## [3.0.0] - 2019-12-16
 
 ### Added