Aarch64 builder image

Please provide an aarch64 builder image such that it can run on aarch64 runners natively:
```
/usr/bin/docker pull bilelmoussaoui/flatpak-github-actions:gnome-45
  gnome-45: Pulling from bilelmoussaoui/flatpak-github-actions
  no matching manifest for linux/arm64/v8 in the manifest list entries
```