build: Add rpm-signature-scan for push pipeline #492

Namespace: <a href="https://detailurl.setting.custom-console-url-namespace.is.not.configured" rel="nofollow">insights-management-tenant
PipelineRun: <a href="https://console.redhat.com/application-pipeline/ns/insights-management-tenant/pipelinerun/provisioning-frontend-on-pull-request-6p9k7" rel="nofollow">provisioning-frontend-on-pull-request-6p9k7

Success

Red Hat Konflux/provisioning-frontend-on-pull-request has successfully validated your commit.

Status	Duration	Name
✅ Succeeded	8 seconds	init
✅ Succeeded	15 seconds	clone-repository-oci-ta
✅ Succeeded	21 seconds	clone-repository
✅ Succeeded	25 seconds	parse-build-deploy-script
✅ Succeeded	2 minutes	create-frontend-dockerfile
✅ Succeeded	1 minute	build-container
✅ Succeeded	10 seconds	build-image-index
✅ Succeeded	38 seconds	clair-scan
✅ Succeeded	9 seconds	apply-tags
✅ Succeeded	13 seconds	push-dockerfile
✅ Succeeded	58 seconds	clamav-scan
✅ Succeeded	25 seconds	ecosystem-cert-preflight-checks
✅ Succeeded	18 seconds	sast-snyk-check
✅ Succeeded	10 seconds	deprecated-base-image-check
✅ Succeeded	10 seconds	rpms-signature-scan
✅ Succeeded	11 seconds	show-summary
✅ Succeeded	7 seconds	show-sbom