[ci skip] Fix typo

Improve external client config

Improve the feature quality of the external client config support by
converting into a behaviour-oriented method.

Fix dialyzer warning on acceptor

Remove Erlang 17 as rebar3 is broken

Update rebar.config to hex.pm compat format

Specific hex.pm packages

Merge branch 'master' of github.com:priestjim/gen_rpc