github: try building arm64 wheels using qemu.

.github/workflows/wheels.yml

@@ -26,13 +26,19 @@ jobs:
         with:
           submodules: true
 
+      - uses: docker/setup-qemu-action@v3
+        if: runner.os == "Linux"
+        with:
+          platforms: "arm64"
+
       - name: Set source timestamp
         run: |
           echo SOURCE_DATE_EPOCH=$(git log -n1 --pretty=%ct) >> "$GITHUB_ENV"
 
       - uses: pypa/[email protected]
         env:
           CIBW_BUILD: "cp312-* pp39-*"
+          CIBW_ARCHS_LINUX: "auto aarch64"
 
       - uses: actions/upload-artifact@v4
         with: