Bump string-length from 4.0.2 to 6.0.0 (#822)

Bumps [string-length](https://github.com/sindresorhus/string-length) from 4.0.2 to 6.0.0.
- [Release notes](https://github.com/sindresorhus/string-length/releases)
- [Commits](sindresorhus/string-length@v4.0.2...v6.0.0)

---
updated-dependencies:
- dependency-name: string-length
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

package-lock.json

@@ -64,7 +64,7 @@
     "read-pkg-up": "^10.1.0",
     "root-check": "^1.0.0",
     "sort-on": "^4.1.1",
-    "string-length": "^4.0.2",
+    "string-length": "^6.0.0",
     "tabtab": "^1.3.2",
     "titleize": "^4.0.0",
     "update-notifier": "^7.3.1",