Update dependency eslint-plugin-flowtype to v8

Author: renovate-bot

{{cookiecutter.project_slug}}/frontend/package-lock.json

@@ -11,7 +11,7 @@
     "@testing-library/user-event": "13.1.9",
     "dotenv": "10.0.0",
     "eslint-config-react-app": "6.0.0",
-    "eslint-plugin-flowtype": "5.7.2",
+    "eslint-plugin-flowtype": "8.0.3",
     "react": "17.0.2",
     "react-dom": "17.0.2",
     "react-scripts": "3.4.4",