fix(ci): add raw.githubusercontent.com to egress allowlist (#364)

Cosign installer fetches its public key from raw.githubusercontent.com,
which was blocked by harden-runner. Add to allowed-endpoints.

🖥️ IDE: [Cursor](https://cursor.sh)
🔌 Extension: [Claude Code](https://claude.ai/download)


Model-Raw: claude-opus-4-6-20250514

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: nullvariant

.github/workflows/publish.yml

@@ -32,6 +32,7 @@ jobs:
             marketplace.visualstudio.com:443
             oauth2.sigstore.dev:443
             objects.githubusercontent.com:443
+            raw.githubusercontent.com:443
             release-assets.githubusercontent.com:443
             open-vsx.org:443
             pkg-containers.githubusercontent.com:443