Update serverless-offline to the latest version 🚀 (#45)

* chore(package): update serverless-offline to version 4.0.0

* chore(package): update lockfile yarn.lock

Author: greenkeeper[bot]

package.json

@@ -39,7 +39,7 @@
     "nodemon": "^1.18.9",
     "prettier": "^1.14.2",
     "serverless": "^1.32.0",
-    "serverless-offline": "^3.25.10",
+    "serverless-offline": "^4.0.0",
     "serverless-webpack": "^5.2.0",
     "ts-jest": "^23.10.5",
     "ts-loader": "^5.3.1",