fix: upgrade axios from 0.20.0 to 0.21.0

Snyk has created this PR to upgrade axios from 0.20.0 to 0.21.0.

See this package in npm:
https://www.npmjs.com/package/axios

See this project in Snyk:
https://app.snyk.io/org/wambugucoder/project/239fdf17-72a9-4c3a-bb51-5d70801ea9b2?utm_source=github&utm_medium=upgrade-pr

Author: snyk-bot

client/package-lock.json

@@ -6,7 +6,7 @@
     "@testing-library/jest-dom": "^4.2.4",
     "@testing-library/react": "^9.5.0",
     "@testing-library/user-event": "^7.2.1",
-    "axios": "^0.20.0",
+    "axios": "^0.21.0",
     "react": "^16.14.0",
     "react-dom": "^16.14.0",
     "react-google-button": "^0.7.1",