chore(deps-dev): bump prettier from 2.3.2 to 2.4.0 in /microsite

Bumps [prettier](https://github.com/prettier/prettier) from 2.3.2 to 2.4.0.
- [Release notes](https://github.com/prettier/prettier/releases)
- [Changelog](https://github.com/prettier/prettier/blob/main/CHANGELOG.md)
- [Commits](https://github.com/prettier/prettier/compare/2.3.2...2.4.0)

---
updated-dependencies:
- dependency-name: prettier
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

microsite/package.json

@@ -19,7 +19,7 @@
     "@spotify/prettier-config": "^11.0.0",
     "docusaurus": "^2.0.0-alpha.70",
     "js-yaml": "^4.1.0",
-    "prettier": "^2.3.2",
+    "prettier": "^2.4.0",
     "yarn-lock-check": "^1.0.5"
   },
   "prettier": "@spotify/prettier-config"