Fixed typo

readme.md

-# Sprinb Boot version of the Spring PetClinic Sample Application [![Build Status](https://travis-ci.org/spring-projects/spring-petclinic.png?branch=master)](https://travis-ci.org/spring-projects/spring-petclinic/)
+# Spring Boot version of the Spring PetClinic Sample Application [![Build Status](https://travis-ci.org/spring-projects/spring-petclinic.png?branch=master)](https://travis-ci.org/spring-projects/spring-petclinic/)
 
 ## Understanding the Spring Petclinic application with a few diagrams
 <a href="https://speakerdeck.com/michaelisvy/spring-petclinic-sample-application">See the presentation here</a>