build(deps): bump actions/attest from 4.2.0 to 4.2.1 (#295)

Bumps [actions/attest](https://github.com/actions/attest) from 4.2.0 to 4.2.1.
- [Release notes](https://github.com/actions/attest/releases)
- [Changelog](https://github.com/actions/attest/blob/main/RELEASE.md)
- [Commits](actions/attest@f7c74d2...508db95)

---
updated-dependencies:
- dependency-name: actions/attest
  dependency-version: 4.2.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/omnarad-release.yaml

@@ -208,7 +208,7 @@ jobs:
           OMNARAD_VERSION: ${{ needs.metadata.outputs.version }}
         run: go run ./tools/omnarad-release verify --dir release
 
-      - uses: actions/attest@f7c74d28b9d84cb8768d0b8ca14a4bac6ef463e6 # v4.2.0
+      - uses: actions/attest@508db95dd578ae2727ebd6217d5ba78e4fbda05d # v4.2.1
         with:
           subject-path: release/*