Bump undici from 5.28.5 to 5.29.0 in /fixtures/import-npm (#9270)

Bumps [undici](https://github.com/nodejs/undici) from 5.28.5 to 5.29.0.
- [Release notes](https://github.com/nodejs/undici/releases)
- [Commits](nodejs/undici@v5.28.5...v5.29.0)

---
updated-dependencies:
- dependency-name: undici
  dependency-version: 5.29.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

fixtures/import-npm/packages/import-example/package.json

@@ -15,7 +15,7 @@
 	},
 	"devDependencies": {
 		"@cloudflare/workers-tsconfig": "../../../../packages/workers-tsconfig",
-		"undici": "^5.28.5",
+		"undici": "^5.29.0",
 		"wrangler": "../../../../packages/wrangler"
 	}
 }