Added rebar3_hex for publishing

Merge pull request #12 from avanier/feature/add_hex.pm_release_support

Add hex.pm release support

Added cache, ran Gradualizer

This is not 100% type-checked; Gradualizer had some errors while running, but it did catch quite a few things.

0.3.1

Fix token conversion

Replace buoy with httpc

Merge pull request #7 from rkallos/upkeep/remove-buoy

Remove buoy

0.2.4: Merge pull request #6 from rkallos/fix/get-creds-from-env

Suppress reauth with a provided token

0.2.3: Merge pull request #5 from rkallos/fix/get-creds-from-env

Fix/get creds from env

Initial release

Merge pull request #1 from rkallos/feature/implement-mvp

Feature/implement mvp