update doc

README.md

@@ -1,20 +1,20 @@
 ![php-excel](resource/logo.png)
 
 <div align=center>
-<img src="https://travis-ci.org/viest/php-ext-xlswriter.svg?branch=master"/>
-<img src="https://ci.appveyor.com/api/projects/status/w4cfjo9e4gsrs6rn/branch/master?svg=true"/>
-<img src="https://img.shields.io/github/release/viest/php-ext-excel-export.svg"/>
+<a href="https://travis-ci.org/viest/php-ext-xlswriter"><img src="https://travis-ci.org/viest/php-ext-xlswriter.svg?branch=master"/></a>
+<a href="https://ci.appveyor.com/project/viest/php-ext-excel-export/branch/master"><img src="https://ci.appveyor.com/api/projects/status/w4cfjo9e4gsrs6rn/branch/master?svg=true"/></a>
+<a href="https://github.com/viest/php-ext-xlswriter/releases"><img src="https://img.shields.io/github/release/viest/php-ext-excel-export.svg"/></a>
 </div>
 
-[![Build Status](https://travis-ci.org/viest/php-ext-xlswriter.svg?branch=master)](https://travis-ci.org/viest/php-ext-xlswriter)
-[![Build status](https://ci.appveyor.com/api/projects/status/w4cfjo9e4gsrs6rn/branch/master?svg=true)](https://ci.appveyor.com/project/viest/php-ext-excel-export/branch/master)
-[![Financial Contributors on Open Collective](https://opencollective.com/php-ext-xlswriter/all/badge.svg?label=financial+contributors)](https://opencollective.com/php-ext-xlswriter)
-[![](https://img.shields.io/badge/PHP-%3E%3D%207.0-brightgreen.svg)](https://github.com/viest/php-ext-xlswriter)
-[![](https://img.shields.io/github/contributors/viest/php-ext-excel-export.svg)](https://github.com/viest/php-ext-xlswriter)
-[![](https://img.shields.io/badge/platform-macos%20%7C%20linux%20%7C%20windows-brightgreen.svg)](https://github.com/viest/php-ext-xlswriter)
-[![](https://img.shields.io/badge/license-BSD-green.svg)](https://github.com/viest/php-ext-xlswriter)
-[![](https://img.shields.io/github/issues/viest/php-ext-excel-export.svg)](https://github.com/viest/php-ext-xlswriter)
-[![FOSSA Status](https://app.fossa.io/api/projects/git%2Bgithub.com%2Fviest%2Fphp-ext-xlswriter.svg?type=shield)](https://app.fossa.io/projects/git%2Bgithub.com%2Fviest%2Fphp-ext-xlswriter?ref=badge_shield)
+<div align=center>
+<a href="https://opencollective.com/php-ext-xlswriter"><img src="https://opencollective.com/php-ext-xlswriter/all/badge.svg?label=financial+contributors"/></a>
+<a href="https://github.com/viest/php-ext-xlswriter"><img src="https://img.shields.io/badge/PHP-%3E%3D%207.0-brightgreen.svg"/></a>
+<a href="https://github.com/viest/php-ext-xlswriter"><img src="https://img.shields.io/github/contributors/viest/php-ext-excel-export.svg"/></a>
+<a href="https://github.com/viest/php-ext-xlswriter"><img src="https://img.shields.io/badge/platform-macos%20%7C%20linux%20%7C%20windows-brightgreen.svg"/></a>
+<a href="https://github.com/viest/php-ext-xlswriter"><img src="https://img.shields.io/badge/license-BSD-green.svg"/></a>
+<a href="https://github.com/viest/php-ext-xlswriter"><img src="https://img.shields.io/github/issues/viest/php-ext-excel-export.svg"/></a>
+<a href="https://app.fossa.io/projects/git%2Bgithub.com%2Fviest%2Fphp-ext-xlswriter?ref=badge_shield"><img src="https://app.fossa.io/api/projects/git%2Bgithub.com%2Fviest%2Fphp-ext-xlswriter.svg?type=shield"/></a>
+</div>
 
 #### Why use xlswriter