explicit docker install?

.gitea/workflows/build.yaml

@@ -25,6 +25,8 @@ jobs:
         username: ${{ secrets.docker_username }}
         password: ${{ secrets.docker_password }}
 
+    - name: Set up Docker Buildx
+      uses: https://github.com/docker/setup-buildx-action@v3
 
     - name: Build
       uses: https://github.com/docker/build-push-action@v2