README.md: switch to SVG badges.

diff --git a/README.md b/README.md
index bed558a..bb5fcfb 100644 (file)
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
-[![NPM version](https://badge.fury.io/js/clean-css.png)](https://badge.fury.io/js/clean-css)
-[![Build Status](https://secure.travis-ci.org/GoalSmashers/clean-css.png)](https://travis-ci.org/GoalSmashers/clean-css)
-[![Dependency Status](https://david-dm.org/GoalSmashers/clean-css.png?theme=shields.io)](https://david-dm.org/GoalSmashers/clean-css)
-[![devDependency Status](https://david-dm.org/GoalSmashers/clean-css/dev-status.png?theme=shields.io)](https://david-dm.org/GoalSmashers/clean-css#info=devDependencies)
+[![NPM version](https://badge.fury.io/js/clean-css.svg)](https://badge.fury.io/js/clean-css)
+[![Build Status](https://secure.travis-ci.org/GoalSmashers/clean-css.svg)](https://travis-ci.org/GoalSmashers/clean-css)
+[![Dependency Status](https://david-dm.org/GoalSmashers/clean-css.svg?theme=shields.io)](https://david-dm.org/GoalSmashers/clean-css)
+[![devDependency Status](https://david-dm.org/GoalSmashers/clean-css/dev-status.svg?theme=shields.io)](https://david-dm.org/GoalSmashers/clean-css#info=devDependencies)
 
 ## What is clean-css?