Adding a non-string to a list

It seems that [the logic for the `add` command](https://github.com/bazelbuild/buildtools/blob/34d7371037136c478031f03a11692fb16ec5e11a/edit/buildozer.go#L81-L92) to buildozer adds `"` quotes around the item to be added unless it knows that the list it's adding to is a list of ints.

Can you add an `add_raw` command for the (admittedly rare) scenario that someone wants to add a non-string item to a list. For my use-case all of the `add`s I want to do are of this nature, so a commandline flag to change the behavior of `add` for the duration of one invocation would also work for me.