feat: upgrade undici from 5.28.4 to 7.15.0

Snyk has created this PR to upgrade undici from 5.28.4 to 7.15.0.

See this package in npm:
undici

See this project in Snyk:
https://app.snyk.io/org/nerds-github/project/00eaf84d-a05e-4e1a-923e-697960352bb8?utm_source=github&utm_medium=referral&page=upgrade-pr

Author: snyk-bot

packages/attest/package.json

@@ -39,7 +39,7 @@
     "@sigstore/rekor-types": "^2.0.0",
     "@types/jsonwebtoken": "^9.0.6",
     "nock": "^13.5.1",
-    "undici": "^5.28.4"
+    "undici": "^7.15.0"
   },
   "dependencies": {
     "@actions/core": "^1.10.1",