Update actions/attest-build-provenance action to v4

Author: renovate[bot]

.github/workflows/docker.yaml

@@ -45,7 +45,7 @@ jobs:
           labels: ${{ steps.meta.outputs.labels }}
 
       - name: Generate artifact attestation
-        uses: actions/attest-build-provenance@v3
+        uses: actions/attest-build-provenance@v4
         with:
           subject-name: index.docker.io/alexiri/alexa2anylist
           subject-digest: ${{ steps.push.outputs.digest }}