Bump actions/attest-build-provenance from 1 to 2 (#47)

Author: dependabot[bot]

.github/workflows/publish.yml

@@ -44,7 +44,7 @@ jobs:
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
       - name: Generate artifact attestation
-        uses: actions/attest-build-provenance@v1
+        uses: actions/attest-build-provenance@v2
         with:
           subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME}}
           subject-digest: ${{ steps.push.outputs.digest }}