Using `make_dataclasses` to handle new keys

[skoudoro]

ok, I might have found a solution using make_dataclasses. e.g: https://stackoverflow.com/a/52536584/17925831

I will try to add that this weekend

Originally posted by @skoudoro in https://github.com/skoudoro/mailerlite-api-python/issues/43#issuecomment-1022272703

[skoudoro]

finally, I use namedtuple and not dataclasses.... so here is a workaround: https://stackoverflow.com/a/28500620/17925831