We've run into issues with publishing to hex.pm in the past; most recently (for the 2.1.0 release), I couldn't publish due to an old lfe.app in ./ebin. At the very least, we need to update the clean target (if we have one?! -- add one if we don't!).

While we're at it, we should address the warnings we get from hex.pm, since with the release of hex 7.1, we're going to get errors instead of warnings ...

Tasks:

• Remove commented-out rebar3_lfe dep
• Update hex.pm metadata
  • fully-qualified OS licence name
  • remove deprecated maintainers field
• Use rebar3 hex publish package to silence docs warnings
• Make sure the clean is run before publishing