Update dependency @cloudflare/vitest-pool-workers to v0.12.8

Author: renovate[bot]

package-lock.json

@@ -23,7 +23,7 @@
     "semver": "^7.7.2"
   },
   "devDependencies": {
-    "@cloudflare/vitest-pool-workers": "0.12.6",
+    "@cloudflare/vitest-pool-workers": "0.12.8",
     "@types/node": "24.10.9",
     "@types/semver": "7.7.1",
     "@typescript-eslint/eslint-plugin": "8.53.1",