Fix lint for attest-build-provenance action

[grem11n]

This should fix a false positive for a popular actions/attest-build-provenance action.

Error message from Super Linter that uses actionlint under the hood:

  ------
  .github/workflows/release.yaml:51:11: input "subject-checksums" is not defined in action "actions/attest-build-provenance@v2". available inputs are "github-token", "push-to-registry", "show-summary", "subject-digest", "subject-name", "subject-path" [action]
     |
  51 |           subject-checksums: ./dist/checksums.txt
     |           ^~~~~~~~~~~~~~~~~~
  ------

Meanwhile, the action README says:

...

    # Path to checksums file containing digest and name of subjects for
    # attestation. Must specify exactly one of "subject-path", "subject-digest",
    # or "subject-checksums".
    subject-checksums:
...