Update ghcr.io/enterprise-contract/golden-container:latest Docker digest to c51af75 (#382)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/checks.yaml

@@ -20,7 +20,7 @@ jobs:
     - name : Run EC Validate (keyless)
       uses: ./
       with:
-        image: ghcr.io/enterprise-contract/golden-container:latest@sha256:95fd8d0017db40e094fc0e2e1ac58d0af1f052722780a7921c5bf989fe2ece59 # latest
+        image: ghcr.io/enterprise-contract/golden-container:latest@sha256:c51af7594a6528006619a10897dcb86e8d1a39deb4f3e5bb6440499092c4dda1 # latest
         identity: https:\/\/github\.com\/(slsa-framework\/slsa-github-generator|enterprise-contract\/golden-container)\/
         issuer: https://token.actions.githubusercontent.com