fix: add contents:read to release job permissions for private repos

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: lostmygithubaccount

.github/workflows/release-rust.yml

@@ -22,6 +22,7 @@ jobs:
     runs-on: ubuntu-latest
     environment: crates-io
     permissions:
+      contents: read
       id-token: write
     steps:
       - uses: actions/checkout@v4