build(deps): bump prop-types from 15.7.2 to 15.8.0 in /docs

Bumps [prop-types](https://github.com/facebook/prop-types) from 15.7.2 to 15.8.0.
- [Release notes](https://github.com/facebook/prop-types/releases)
- [Changelog](https://github.com/facebook/prop-types/blob/main/CHANGELOG.md)
- [Commits](facebook/prop-types@v15.7.2...v15.8.0)

---
updated-dependencies:
- dependency-name: prop-types
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

docs/package.json

@@ -39,7 +39,7 @@
     "gatsby-transformer-yaml": "^2.11.0",
     "polished": "^4.1.3",
     "prism-react-renderer": "^1.2.1",
-    "prop-types": "^15.7.2",
+    "prop-types": "^15.8.0",
     "puppeteer": "^12.0.1",
     "react": "^17.0.2",
     "react-dom": "^17.0.2",