fix(ci): align secrets-scan material name with contract

The secrets-detection contract (revision 5) expects a material named
"secret-report", but the workflow was adding it as "gitleaks-scan",
causing the attestation push to fail with
"some materials have not been crafted yet: secret-report".

Rename the material in the workflow to match the contract.

Signed-off-by: Miguel Martinez Trivino <miguel@chainloop.dev>

Author: migmartri

.github/workflows/secrets-scan-daily.yml

@@ -50,7 +50,7 @@ jobs:
       - name: Add Gitleaks Report to Attestation
         run: |
           chainloop attestation add \
-            --name gitleaks-scan \
+            --name secret-report \
             --value gitleaks-report.json \
             --kind GITLEAKS_JSON