Bump moment from 2.24.0 to 2.29.1 in /packages/playground

Bumps [moment](https://github.com/moment/moment) from 2.24.0 to 2.29.1.
- [Release notes](https://github.com/moment/moment/releases)
- [Changelog](https://github.com/moment/moment/blob/develop/CHANGELOG.md)
- [Commits](https://github.com/moment/moment/compare/2.24.0...2.29.1)

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

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

packages/playground/package.json

@@ -26,7 +26,7 @@
     "lodash": "4.17.15",
     "mathjs": "10.4.1",
     "moduleserve": "0.9.1",
-    "moment": "2.24.0",
+    "moment": "2.29.1",
     "pdfast": "^0.2.0",
     "rationale": "0.2.0",
     "react": "17.0.2",