deps: update babel7 to the latest version 🚀 (#61)

* chore(package): update @babel/core to version 7.4.4

* chore(package): update @babel/preset-env to version 7.4.4

* chore(package): update lockfile yarn.lock

Author: greenkeeper[bot]

package.json

@@ -19,8 +19,8 @@
     "watch:hello": "serverless invoke local --watch --function hello --path fixtures/event.json"
   },
   "devDependencies": {
-    "@babel/core": "7.3.3",
-    "@babel/preset-env": "7.3.1",
+    "@babel/core": "7.4.4",
+    "@babel/preset-env": "7.4.4",
     "@babel/preset-typescript": "^7.3.3",
     "@types/jest": "^24.0.0",
     "@typescript-eslint/eslint-plugin": "^1.6.0",