update readme for babel 7 (#150)

Author: bj00rn

README.md

@@ -1,8 +1,15 @@
 # babel-plugin-react-intl
 
 Extracts string messages for translation from modules that use [React Intl][].
+## Dependencies
 
-_**Note:** This Babel plugin works with React Intl v2.x, and **1.x of this plugin works with Babel 5, 2.x works with Babel 6**._
+### React Intl
+This Babel plugin works with React Intl v2.x
+  
+### Babel
+- **3.x** of this plugin works with Babel 7
+- **2.x** works with Babel 6
+- **1.x** works with Babel 5
 
 ## Installation
 
@@ -47,7 +54,7 @@ If a message descriptor has a `description`, it'll be removed from the source af
 The extract message descriptors are available via the `metadata` property on the object returned from Babel's `transform()` API:
 
 ```javascript
-require('babel-core').transform('code', {
+require('@babel/core').transform('code', {
   plugins: ['react-intl']
 }) // => { code, map, ast, metadata['react-intl'].messages };
 ```