Update README.md

Use link to documentation site in card image

[skip ci]

Author: nelson6e65

README.md

@@ -1,4 +1,4 @@
-![Card](./.github/assets/card.svg)
+[![Card](./.github/assets/card.svg)](https://nelson6e65.github.io/phpdoc-vuepress)
 
 # PHPDoc-VuePress
 [![Travis Build Status](https://img.shields.io/travis/nelson6e65/phpdoc-vuepress/master.svg?logo=travis)](https://travis-ci.org/nelson6e65/phpdoc-vuepress)
@@ -9,7 +9,7 @@
 [![Latest unstable Version](https://img.shields.io/packagist/vpre/nelson6e65/phpdoc-vuepress.svg?label=unstable)](https://packagist.org/packages/nelson6e65/phpdoc-vuepress#dev-master)
 
 [![License](https://img.shields.io/github/license/nelson6e65/phpdoc-vuepress.svg)](LICENSE)
-[![Documentation](http://img.shields.io/badge/📜-Documentation-lightgrey.svg)](http://nelson6e65.github.io/phpdoc-vuepress)
+[![Documentation](http://img.shields.io/badge/📜-Documentation-lightgrey.svg)](https://nelson6e65.github.io/phpdoc-vuepress)
 [![Wakatime](https://wakatime.com/badge/github/nelson6e65/phpdoc-vuepress.svg)](https://wakatime.com/badge/github/nelson6e65/phpdoc-vuepress)