feat: enable building arm64 docker images (osuAkatsuki#658)

* feat: enable building arm64 docker images

* attempt at fixing

* support multiple platform exports

.github/workflows/docker-build.yaml

@@ -19,6 +19,8 @@ jobs:
 
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v3
+        with:
+          platforms: linux/amd64, linux/arm64
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v2
@@ -27,7 +29,8 @@ jobs:
         uses: docker/build-push-action@v5
         with:
           context: .
-          outputs: type=docker,dest=/tmp/docker.tar
+          platforms: linux/amd64, linux/arm64
+          outputs: type=oci,dest=/tmp/docker.tar
           tags: bancho.py:${{ github.sha }}
           cache-from: type=gha
           cache-to: type=gha,mode=max
@@ -50,7 +53,7 @@ jobs:
         if: ${{ github.ref == 'refs/heads/master' }}
         with:
           context: .
-          platforms: linux/amd64
+          platforms: linux/amd64, linux/arm64
           push: true
           tags: |
             ${{ secrets.DOCKERHUB_USERNAME }}/bancho.py:latest