update CHANGELOG.md and README.md for v1.2.0

Author: atercattus

CHANGELOG.md

@@ -1,3 +1,8 @@
+### Tag v1.2.0 (2021.05.16)
+* Fix a rare bug in Conn.readResultStreaming. [#573](https://github.com/go-mysql-org/go-mysql/pull/573) ([atercattus](https://github.com/atercattus))
+* Fix tag. [#575](https://github.com/go-mysql-org/go-mysql/pull/575) ([atercattus](https://github.com/atercattus))
+* Update dependency. [#576](https://github.com/go-mysql-org/go-mysql/pull/576) ([Ehco1996](https://github.com/Ehco1996))
+
 ### Tag v1.1.2 (2021.04.20)
 * Fix canal test in readme. [#516](https://github.com/go-mysql-org/go-mysql/pull/516) ([gaojijun](https://github.com/gaojijun))
 * UUID clone. [#522](https://github.com/go-mysql-org/go-mysql/pull/522) ([lance6716](https://github.com/lance6716))

README.md

@@ -9,10 +9,10 @@ A pure go library to handle MySQL network protocol and replication.
 ## How to migrate to this repo
 To change the used package in your repo it's enough to add this `replace` directive to your `go.mod`:
 ```
-replace github.com/siddontang/go-mysql => github.com/go-mysql-org/go-mysql v1.1.2
+replace github.com/siddontang/go-mysql => github.com/go-mysql-org/go-mysql v1.2.0
 ```
 
-v1.1.2 - is the last tag in repo, feel free to choose what you want.
+v1.2.0 - is the last tag in repo, feel free to choose what you want.
 
 ## Changelog
 This repo uses [Changelog](CHANGELOG.md).