The `buildContainerImage2` function assumes the default branch name is
*main*, but it's *master* for this repository. If this is not correct,
the `latest` tag will not be updated in the container registry.
The `buildContainerImage2` function now accepts a `pi` argument, which
controls whether or not the build can run on a Raspberry Pi. Since the
only reason we were not using this function before was to avoid building
on a Pi, we no longer need the custom code.
