Explicitly set up QEMU to try and work around CI trouble

Related to https://github.com/etkecc/baibot/issues/2

We've had a few more instances of the same issue since then.

.github/workflows/workflow.yml

@@ -24,6 +24,10 @@ jobs:
     name: Build and Publish
     runs-on: self-hosted
     steps:
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+        with:
+          platforms: arm64
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v1
       - name: Login to ghcr.io