docs: add mascot

Author: Kent C. Dodds

README.md

@@ -1,6 +1,10 @@
 <div align="center">
 <h1>cypress-testing-library</h1>
 
+<a href="https://www.emojione.com/emoji/1f405">
+<img height="80" width="80" alt="tiger" src="https://raw.githubusercontent.com/kentcdodds/dom-testing-library/master/other/tiger.png" />
+</a>
+
 <p>Simple and complete custom Cypress commands and utilities that encourage good testing practices.</p>
 </div>