Change the license notation in the package.json file.

Author: yoichiro

package.json

@@ -2,7 +2,7 @@
     "name": "actions-on-google-testing",
     "description": "This is an end-to-end testing library for developers building actions",
     "version": "0.1.0",
-    "license": "Apache Version 2.0",
+    "license": "Apache-2.0",
     "author": "Google Inc.",
     "main": "dist/index.js",
     "types": "dist/index.d.ts",