Bump @types/mock-fs from 4.13.3 to 4.13.4 in /test/util

Bumps [@types/mock-fs](https://github.com/DefinitelyTyped/DefinitelyTyped/tree/HEAD/types/mock-fs) from 4.13.3 to 4.13.4.
- [Release notes](https://github.com/DefinitelyTyped/DefinitelyTyped/releases)
- [Commits](https://github.com/DefinitelyTyped/DefinitelyTyped/commits/HEAD/types/mock-fs)

---
updated-dependencies:
- dependency-name: "@types/mock-fs"
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

test/util/package.json

@@ -19,7 +19,7 @@
     "@types/glob-to-regexp": "^0.4.1",
     "@types/mdast": "^4.0.0",
     "@types/mocha": "^10.0.3",
-    "@types/mock-fs": "^4.13.3",
+    "@types/mock-fs": "^4.13.4",
     "@types/node": "^20.8.10",
     "@types/sinon": "^10.0.16",
     "@types/unist": "^3.0.1",