ci: fix subject name

Author: LogCreative

.github/workflows/docker-publish.yml

@@ -73,6 +73,6 @@ jobs:
       - name: Generate artifact attestation
         uses: actions/attest-build-provenance@v1
         with:
-          subject-name: ghcr.io/${{ github.repository }}
+          subject-name: ghcr.io/logcreative/pgfplotsedt
           subject-digest: ${{ steps.build-and-push.outputs.digest }}
           push-to-registry: true