build(deps): bump react-helmet from 5.2.1 to 6.1.0 in /docs (#1290)

Bumps [react-helmet](https://github.com/nfl/react-helmet) from 5.2.1 to 6.1.0.
- [Release notes](https://github.com/nfl/react-helmet/releases)
- [Changelog](https://github.com/nfl/react-helmet/blob/master/CHANGELOG.md)
- [Commits](https://github.com/nfl/react-helmet/commits/6.1.0)

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

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs/package-lock.json

@@ -45,7 +45,7 @@
     "react": "^16.12.0",
     "react-dom": "^16.12.0",
     "react-headroom": "^3.0.0",
-    "react-helmet": "^5.2.1",
+    "react-helmet": "^6.1.0",
     "react-icons": "^3.10.0",
     "react-live": "^2.2.2",
     "url-join": "^4.0.1"