docs: remove 'v1.x' from demo link

[ci skip]

README.md

@@ -15,7 +15,7 @@
 
 ![ReDoc demo](https://raw.githubusercontent.com/Rebilly/ReDoc/master/demo/redoc-demo.png)
 
-## [Live demo (v1.x)](http://rebilly.github.io/ReDoc/)
+## [Live demo](http://rebilly.github.io/ReDoc/)
 
 [<img alt="Deploy to Github" src="http://i.imgur.com/YZmaqk3.png" height="60px">](https://github.com/Rebilly/generator-openapi-repo#generator-openapi-repo--) [<img alt="ReDoc as a service" src="http://i.imgur.com/edqdCv6.png" height="60px">](https://redoc.ly) [<img alt="Customization services" src="http://i.imgur.com/c4sUF7M.png" height="60px">](https://redoc.ly/#services)