replace preset-es2015 with preset-env (#5346)

preset-es2015 was already deprecated and should be replaced by preset-env

Author: nicholaslee119

docs/GettingStarted.md

@@ -97,12 +97,12 @@ _Note: Explicitly installing `regenerator-runtime` is not needed if you use
 Don't forget to add a [`.babelrc`](https://babeljs.io/docs/usage/babelrc/) file
 in your project's root folder. For example, if you are using ES6 and
 [React.js](https://facebook.github.io/react/) with the
-[`babel-preset-es2015`](https://babeljs.io/docs/plugins/preset-es2015/) and
+[`babel-preset-env`](https://babeljs.io/docs/plugins/preset-env/) and
 [`babel-preset-react`](https://babeljs.io/docs/plugins/preset-react/) presets:
 
 ```json
 {
-  "presets": ["es2015", "react"]
+  "presets": ["env", "react"]
 }
 ```
 
@@ -113,16 +113,16 @@ You are now set up to use all ES6 features and React specific syntax.
 > `test`. It will not use `development` section like Babel does by default when
 > no `NODE_ENV` is set.
 
-> Note: If you've turned off transpilation of ES2015 modules with the option
+> Note: If you've turned off transpilation of ES6 modules with the option
 > `{ "modules": false }`, you have to make sure to turn this on in your test
 > environment.
 
 ```json
 {
-  "presets": [["es2015", {"modules": false}], "react"],
+  "presets": [["env", {"modules": false}], "react"],
   "env": {
     "test": {
-      "presets": [["es2015"], "react"]
+      "presets": [["env"], "react"]
     }
   }
 }