Update README.md

Author: yeonjuan

README.md

@@ -6,6 +6,6 @@ An online demo for [typescript-eslint](https://github.com/typescript-eslint/type
 
 ## Development
 
-* `npm run dev` : run webpack dev server on http:localhost:8080
+* `npm run dev` : run webpack dev server on http://localhost:8080
 * `npm run format` : format code with prettier
 * `npm run test`: run test