update CHANGELOG.md

Author: KoyanagiHitoshi

CHANGELOG.md

@@ -1,13 +1,17 @@
 # Change Log
 
+## [v1.2.0](https://github.com/KoyanagiHitoshi/AtCoder/releases/tag/v1.2.0) / 2020-04-08
+
+* [#5](https://github.com/KoyanagiHitoshi/AtCoder/pull/5) add code
+
 ## [v1.1.1](https://github.com/KoyanagiHitoshi/AtCoder/releases/tag/v1.1.1) / 2020-04-04
 
-* [#4](https://github.com/KoyanagiHitoshi/AtCoder/pull/4) update CHANGELOG.md 
-* [#3](https://github.com/KoyanagiHitoshi/AtCoder/pull/3) update README.md 
-* [#2](https://github.com/KoyanagiHitoshi/AtCoder/pull/2) first commit CHANGELOG.md 
-* [#1](https://github.com/KoyanagiHitoshi/AtCoder/pull/1) update README.md 
+* [#4](https://github.com/KoyanagiHitoshi/AtCoder/pull/4) update CHANGELOG.md
+* [#3](https://github.com/KoyanagiHitoshi/AtCoder/pull/3) update README.md
+* [#2](https://github.com/KoyanagiHitoshi/AtCoder/pull/2) first commit CHANGELOG.md
+* [#1](https://github.com/KoyanagiHitoshi/AtCoder/pull/1) update README.md
 
-## [v1.1.0](https://github.com/KoyanagiHitoshi/AtCoder/releases/tag/v1.1.0) / 2020-03-31
+## v1.1.0 / 2020-03-31
 
 * first commit LICENSE
 * first commit new code