Changed

• Major docs reviews and corrections (thanks to @kianmeng, @andreasknoepfle, Jon Forsyth, @fuelen)
• Change of CI pipeline (thanks to @dolfinus)
• Now uses Elixir 1.8 as minimum (and actually test the mininum version on CI)

Fixed

• Fixed arity of Joken.Config.validate (thanks to @blagh)
• Compatibility with OTP 24.0 with JOSE update to 1.11.2