feat: upgrade @sigstore/sign from 2.3.2 to 3.0.0

Snyk has created this PR to upgrade @sigstore/sign from 2.3.2 to 3.0.0.

See this package in npm:
@sigstore/sign

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

@@ -47,7 +47,7 @@
     "@actions/http-client": "^2.2.3",
     "@octokit/plugin-retry": "^6.0.1",
     "@sigstore/bundle": "^2.3.2",
-    "@sigstore/sign": "^2.3.2",
+    "@sigstore/sign": "^3.0.0",
     "jose": "^5.2.3"
   },
   "overrides": {