Upgrade Babel to 7.0.0-beta.56 (#216)
Upgrade Babel to 7.0.0-beta.56 (#216)

Summary:
**Summary**

This pull request bumps Babel to 7.0.0-beta.56 to incorporate the latest bugfixes from Babel.

**Test plan**

One way to test is to add a simple TypeScript file with a type as the default export:

```typescript
export const test = 1
export default interface A {}
```

and then import that file from any other file:

```js
import { test } from './typescript-test'
```

Before this would throw an error, but with the latest Babel this is now fixed.
Pull Request resolved: https://github.com/facebook/metro/pull/216

Reviewed By: mjesun

Differential Revision: D9216331

Pulled By: rafeca

fbshipit-source-id: a48e87c3c6b2902be410395b1b4afab63cb88fec

javache/react-native,hoangpham95/react-native,exponent/react-native,exponentjs/react-native,pandiaraj44/react-native,hammerandchisel/react-native,javache/react-native,exponent/react-native,hammerandchisel/react-native,hoangpham95/react-native,hammerandchisel/react-native,facebook/react-native,hoangpham95/react-native,hoangpham95/react-native,myntra/react-native,javache/react-native,javache/react-native,myntra/react-native,pandiaraj44/react-native,facebook/react-native,facebook/react-native,myntra/react-native,facebook/react-native,exponentjs/react-native,javache/react-native,arthuralee/react-native,facebook/react-native,exponentjs/react-native,arthuralee/react-native,arthuralee/react-native,hammerandchisel/react-native,javache/react-native,pandiaraj44/react-native,janicduplessis/react-native,pandiaraj44/react-native,arthuralee/react-native,exponent/react-native,javache/react-native,hoangpham95/react-native,exponent/react-native,hammerandchisel/react-native,exponent/react-native,hoangpham95/react-native,myntra/react-native,janicduplessis/react-native,exponent/react-native,hoangpham95/react-native,pandiaraj44/react-native,pandiaraj44/react-native,janicduplessis/react-native,exponent/react-native,exponent/react-native,javache/react-native,myntra/react-native,hammerandchisel/react-native,janicduplessis/react-native,facebook/react-native,myntra/react-native,janicduplessis/react-native,facebook/react-native,janicduplessis/react-native,myntra/react-native,pandiaraj44/react-native,facebook/react-native,pandiaraj44/react-native,janicduplessis/react-native,exponentjs/react-native,hammerandchisel/react-native,hoangpham95/react-native,javache/react-native,exponentjs/react-native,arthuralee/react-native,facebook/react-native,janicduplessis/react-native,myntra/react-native,hammerandchisel/react-native,exponentjs/react-native,exponentjs/react-native,myntra/react-native,exponentjs/react-native