Update CHANGELOG.md

Author: xujiajun

docs/CHANGELOG.md

@@ -55,6 +55,6 @@
 * add cache command for route&config
 
 ## v1.7.3 (2017-10-20)
-* Merge pull request #15 from akiyamaSM/patch-2
+* Merge pull request [#15](https://github.com/tastphp/framework/pull/15) from akiyamaSM/patch-2
 * Fixed when no app.yml file error
-* move register debugbar code to WhoopsExceptionsHandler
+* move register debugbar code to WhoopsExceptionsHandler