Bump eslint from 7.20.0 to 7.21.0 in /packages/webapp

Bumps [eslint](https://github.com/eslint/eslint) from 7.20.0 to 7.21.0.
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](https://github.com/eslint/eslint/compare/v7.20.0...v7.21.0)

Signed-off-by: dependabot[bot] <support@github.com>

packages/webapp/package.json

@@ -36,7 +36,7 @@
   "devDependencies": {
     "cypress": "6.5.0",
     "cypress-file-upload": "5.0.2",
-    "eslint": "7.20.0",
+    "eslint": "7.21.0",
     "eslint-config-prettier": "8.1.0",
     "eslint-plugin-cypress": "2.11.2",
     "eslint-plugin-react": "7.22.0",