fix: 02-Calling-an-API/package.json & 02-Calling-an-API/yarn.lock to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-SERIALIZEJAVASCRIPT-536840

Author: snyk-bot

02-Calling-an-API/package.json

@@ -27,7 +27,7 @@
     "react": "^16.8.6",
     "react-dom": "^16.8.6",
     "react-router-dom": "^5.0.0",
-    "react-scripts": "3.0.1",
+    "react-scripts": "3.3.0",
     "reactstrap": "^8.0.0"
   },
   "devDependencies": {