Apply suggestions from code review

Co-authored-by: Víctor Cuadrado Juan <2196685+viccuad@users.noreply.github.com>
Signed-off-by: José Guilherme Vanz <jvanz@jvanz.com>

Author: jvanz

.github/workflows/container-image.yml

@@ -73,7 +73,7 @@ jobs:
             
           cosign verify \
             --certificate-oidc-issuer=https://token.actions.githubusercontent.com \
-            --certificate-identity-regexp="https://github.com/${{github.repository_owner}}/policy-server/.github/workflows/container-image.yml@${{ github.ref }}" \
+            --certificate-identity="https://github.com/${{github.repository_owner}}/policy-server/.github/workflows/container-image.yml@${{ github.ref }}" \
             ghcr.io/${{github.repository_owner}}/policy-server@${{ steps.build-image.outputs.digest }}
 
       - id: setoutput