chore(npm): update espower-babel

Author: azu

package.json

@@ -35,7 +35,7 @@
     "babel-cli": "^6.1.18",
     "babel-plugin-transform-es2015-modules-commonjs": "^6.1.20",
     "babel-preset-es2015": "^6.1.18",
-    "espower-babel": "^3.3.0",
+    "espower-babel": "^4.0.0",
     "mocha": "^2.3.3",
     "power-assert": "^1.1.0",
     "sentence-splitter": "^1.0.2",