make workflow more generic

.github/workflows/docker-publish.yml

@@ -1,5 +1,8 @@
 name: Build and Push Docker Image to GHCR
 
+env:
+  OCI_TOKEN: ${{ secrets.OCI_TOKEN || secrets.GITHUB_TOKEN }}
+
 on:
   push:
     branches: ["main"]
@@ -20,15 +23,15 @@ jobs:
       - name: Log in to GHCR
         uses: docker/login-action@v3
         with:
-          registry: ghcr.io
+          registry: ${{ vars.OCI_REGISTRY || 'ghcr.io' }}
           username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
+          password: ${{ env.OCI_TOKEN }}
 
       - name: Extract Docker metadata
         id: meta
         uses: docker/metadata-action@v5
         with:
-          images: ghcr.io/${{ github.repository }}
+          images: ${{ vars.OCI_REGISTRY || 'ghcr.io' }}/${{ github.repository }}
 
       - name: Build and push Docker image
         uses: docker/build-push-action@v6