ci: sign images recursively (#10)

Author: rare-magma

.github/workflows/docker.yml

@@ -58,7 +58,7 @@ jobs:
           DIGEST="$(skopeo inspect docker://${IMAGE} | jq -r .Digest)"
           echo "digest=${DIGEST}" >> "$GITHUB_OUTPUT"
 
-          cosign sign --recursively --yes "${IMAGE}@${DIGEST}"
+          cosign sign --recursive --yes "${IMAGE}@${DIGEST}"
 
       - name: Generate artifact attestation
         uses: actions/attest-build-provenance@977bb373ede98d70efdf65b84cb5f73e068dcc2a # ratchet:actions/attest-build-provenance@v2