Re-enable provenance attestation verification for distroless images

[politician]

Waiting for GoogleContainerTools/distroless#975 to be resolved

Un-comment to re-enable:

app-node-js/.github/workflows/publish.yaml

Lines 57 to 61 in bd19428

	# https://github.com/GoogleContainerTools/distroless/issues/975
	# - name: Verify base image provenance
	# run: cosign verify-attestation --key .keys/distroless.pub gcr.io/distroless/nodejs:$NODE_VERSION
	# env:
	# NODE_VERSION: ${{ steps.node_version.outputs.version }}