ci: add missing dockerfile path

Author: sdellaco

.github/workflows/build.yaml

@@ -38,6 +38,7 @@ jobs:
         uses: docker/build-push-action@v6
         with:
           context: .
+          file: Dockerfile.linux
           push: ${{ github.event_name != 'pull_request' }}
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}