Update version number.

dist/js/splide.js

@@ -1,6 +1,6 @@
 /*!
  * Splide.js
- * Version  : 2.1.0
+ * Version  : 2.2.0
  * License  : MIT
  * Copyright: 2019 Naotoshi Fujita
  */

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "@splidejs/splide",
-  "version": "2.1.0",
+  "version": "2.2.0",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@splidejs/splide",
-  "version": "2.1.0",
+  "version": "2.2.0",
   "description": "Splide is a lightweight and powerful slider without any dependencies.",
   "author": "Naotoshi Fujita",
   "license": "MIT",