fix: use GHCR_LOGIN/GHCR_PASSWORD secrets for container registry auth

Author: butschster

.github/workflows/deploy.yml

@@ -25,8 +25,8 @@ jobs:
         uses: docker/login-action@v3
         with:
           registry: ${{ env.REGISTRY }}
-          username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
+          username: ${{ secrets.GHCR_LOGIN }}
+          password: ${{ secrets.GHCR_PASSWORD }}
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3