docs: add multi-platform build example to README

README.md

@@ -44,9 +44,47 @@ jobs:
 >       name: Set up QEMU
 >       uses: docker/setup-qemu-action@v3
 >     -
->       name: Set up Docker Buildx
->       uses: docker/setup-buildx-action@v3
-> ```
+-
+  name: Set up Docker Buildx
+  uses: docker/setup-buildx-action@v3
+```
+
+### Multi-platform build example
+
+The following example shows how to use this action to build and push a multi-platform image for `linux/amd64` and `linux/arm64` using [Buildx](https://github.com/docker/buildx):
+
+```yaml
+name: ci
+
+on:
+push:
+branches:
+- 'main'
+
+jobs:
+docker:
+runs-on: ubuntu-latest
+steps:
+-
+  name: Set up QEMU
+  uses: docker/setup-qemu-action@v3
+-
+  name: Set up Docker Buildx
+  uses: docker/setup-buildx-action@v3
+-
+  name: Login to Docker Hub
+  uses: docker/login-action@v3
+  with:
+    username: ${{ secrets.DOCKERHUB_USERNAME }}
+    password: ${{ secrets.DOCKERHUB_TOKEN }}
+-
+  name: Build and push
+  uses: docker/build-push-action@v6
+  with:
+    push: true
+    tags: user/app:latest
+    platforms: linux/amd64,linux/arm64
+```
 
 ## Customizing