Update babel-preset-env to 0.0.8

Changes between 0.0.6 and 0.0.8 should be backwards compatible:
https://github.com/babel/babel-preset-env/blob/master/CHANGELOG.md

Author: valscion

packages/babel-preset-react-app/package.json

@@ -20,7 +20,7 @@
     "babel-plugin-transform-react-jsx-source": "6.9.0",
     "babel-plugin-transform-regenerator": "6.16.1",
     "babel-plugin-transform-runtime": "6.15.0",
-    "babel-preset-env": "0.0.6",
+    "babel-preset-env": "0.0.8",
     "babel-preset-latest": "6.16.0",
     "babel-preset-react": "6.16.0",
     "babel-runtime": "6.11.6"