generate-slsa

Add a SLSA Generation step (YAML type: provenance) to an existing Harness pipeline to generate SLSA provenance and optionally attest with Cosign (keyless, key-based, or Vault). Supports container images (Docker, ECR, GCR, GAR, ACR, HAR) and Harness Local Stage artifacts. Place after image build/push; run sequentially after SBOM steps, not in parallel. Only works with existing pipelines. Use when asked to generate…