update README.md

Author: Apple

README.md

@@ -1,6 +1,6 @@
 # Android OCR
 
-![Platform](https://img.shields.io/badge/platform-Android-yellow.svg)](https://www.android.com)
+[![Platform](https://img.shields.io/badge/platform-Android-yellow.svg)](https://www.android.com)
 [![License](https://img.shields.io/badge/license-Apache%202-4EB1BA.svg?style=flat-square)](https://www.apache.org/licenses/LICENSE-2.0.html)
 [![Gradle Version](https://img.shields.io/badge/gradle-4.0-green.svg)](https://docs.gradle.org/current/release-notes)
 [![Awesome Badge](https://cdn.rawgit.com/sindresorhus/awesome/d7305f38d29fed78fa85652e3a63e154dd8e8829/media/badge.svg)](https://java-lang.github.io/awesome-java)