Fix README typo

README.md

@@ -26,8 +26,8 @@ import Keyboard from 'simple-keyboard';
 import 'simple-keyboard/build/css/index.css';
 
 let keyboard = new Keyboard({
-  onChange: input => this.onChange(input),
-  onKeyPress: button => this.onKeyPress(button)
+  onChange: input => onChange(input),
+  onKeyPress: button => onKeyPress(button)
 });
 
 function onChange(input){

package.json

@@ -1,6 +1,6 @@
 {
   "name": "simple-keyboard",
-  "version": "2.3.21",
+  "version": "2.3.22",
   "description": "On-screen Virtual Keyboard",
   "main": "build/index.js",
   "scripts": {