Reduce size of logo in readme

readme.md

@@ -1,4 +1,4 @@
-# [![AVA](media/header.png)](https://ava.li)
+# <img src="media/header.png" title="AVA" alt="AVA logo" width="530">
 
 [![Build Status](https://travis-ci.org/avajs/ava.svg?branch=master)](https://travis-ci.org/avajs/ava)  [![Coverage Status](https://codecov.io/gh/avajs/ava/branch/master/graph/badge.svg)](https://codecov.io/gh/avajs/ava/branch/master) [![XO code style](https://img.shields.io/badge/code_style-XO-5ed9c7.svg)](https://github.com/xojs/xo) [![Join the community on Spectrum](https://withspectrum.github.io/badge/badge.svg)](https://spectrum.chat/ava)
 [![Mentioned in Awesome Node.js](https://awesome.re/mentioned-badge.svg)](https://github.com/sindresorhus/awesome-nodejs)