chore(deps-dev): bump undici from 5.28.3 to 6.9.0

Bumps [undici](https://github.com/nodejs/undici) from 5.28.3 to 6.9.0.
- [Release notes](https://github.com/nodejs/undici/releases)
- [Commits](nodejs/undici@v5.28.3...v6.9.0)

---
updated-dependencies:
- dependency-name: undici
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

package.json

@@ -36,7 +36,7 @@
     "standard": "^17.0.0-2",
     "tap": "^16.0.0",
     "tsd": "^0.30.0",
-    "undici": "^5.0.0"
+    "undici": "^6.9.0"
   },
   "dependencies": {
     "fastify": "^4.16.3"