Don't use buildx

Author: SystemKeeper

.github/workflows/build-test.yml

@@ -67,4 +67,4 @@ jobs:
       if: ${{ startsWith(matrix.dockerfile, 'client') }}
       run: |
         cd "$(dirname ${{ matrix.dockerfile }})"
-        docker buildx build --platform linux/amd64 . --file dockerfile
+        docker build . --file Dockerfile