chapter 03: install @types/node, with that, I can work with types and node.js modules without vscode warnings

Author: devcorpio

package-lock.json

@@ -17,6 +17,7 @@
     },
     "homepage": "https://github.com/devcorpio/the-art-of-unit-testing#readme",
     "devDependencies": {
+        "@types/node": "^10.12.18",
         "husky": "^1.3.1",
         "jest": "^23.6.0",
         "prettier": "1.15.3",