chore(package): update babel-core to version 6.7.4

http://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -33,7 +33,7 @@
   "homepage": "https://github.com/iamstarkov/import-list-from-string#readme",
   "devDependencies": {
     "babel-cli": "^6.1.2",
-    "babel-core": "^6.1.2",
+    "babel-core": "^6.7.4",
     "babel-plugin-add-module-exports": "^0.1.2",
     "babel-preset-es2015": "^6.1.2",
     "coveralls": "^2.11.8",