chore(deps-dev): bump @cloudflare/vitest-pool-workers

Bumps [@cloudflare/vitest-pool-workers](https://github.com/cloudflare/workers-sdk/tree/HEAD/packages/vitest-pool-workers) from 0.18.8 to 0.20.2.
- [Release notes](https://github.com/cloudflare/workers-sdk/releases)
- [Changelog](https://github.com/cloudflare/workers-sdk/blob/main/packages/vitest-pool-workers/CHANGELOG.md)
- [Commits](https://github.com/cloudflare/workers-sdk/commits/@cloudflare/vitest-pool-workers@0.20.2/packages/vitest-pool-workers)

---
updated-dependencies:
- dependency-name: "@cloudflare/vitest-pool-workers"
  dependency-version: 0.20.2
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

package.json

@@ -20,7 +20,7 @@
     "postinstall": "wrangler types"
   },
   "devDependencies": {
-    "@cloudflare/vitest-pool-workers": "^0.18.8",
+    "@cloudflare/vitest-pool-workers": "^0.20.2",
     "@types/node": "^26.1.1",
     "prettier": "^3.9.6",
     "typescript": "^7.0.2",