update CHANGELOG.md

Author: jojoliang

CHANGELOG.md

@@ -7,19 +7,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 Generated by [`auto-changelog`](https://github.com/CookPete/auto-changelog).
 
-## [v0.7.28](https://github.com/tencentyun/cos-go-sdk-v5/compare/v0.7.27...v0.7.28) - 2021-07-21
-
-update context
-
-### Merged
-
-- update context [`#143`](https://github.com/tencentyun/cos-go-sdk-v5/pull/143)
-- update ctx [`#141`](https://github.com/tencentyun/cos-go-sdk-v5/pull/141)
-
-### Commits
-
-- Updated CHANGELOG.md [`925081a`](https://github.com/tencentyun/cos-go-sdk-v5/commit/925081ac2523e9e92ddd17c27fc5ab965b8e3648)
-
 ## [v0.7.27](https://github.com/tencentyun/cos-go-sdk-v5/compare/v0.7.26...v0.7.27) - 2021-06-25
 
 fix the go.mod