Bump actions/attest-build-provenance from 1.4.4 to 2.0.1 (#600)

Bumps [actions/attest-build-provenance](https://github.com/actions/attest-build-provenance) from 1.4.4 to 2.0.1.
- [Release notes](https://github.com/actions/attest-build-provenance/releases)
- [Changelog](https://github.com/actions/attest-build-provenance/blob/main/RELEASE.md)
- [Commits](actions/attest-build-provenance@ef24412...c4fbc64)

---
updated-dependencies:
- dependency-name: actions/attest-build-provenance
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/release.yml

@@ -62,7 +62,7 @@ jobs:
           COSIGN_YES: true
 
       - name: Generate build provenance attestation
-        uses: actions/attest-build-provenance@ef244123eb79f2f7a7e75d99086184180e6d0018 # v1.4.4
+        uses: actions/attest-build-provenance@c4fbc648846ca6f503a13a2281a5e7b98aa57202 # v2.0.1
         with:
           subject-name: ghcr.io/sigstore/gitsign
           subject-digest: ${{ steps.digest.outputs.digest }}