v2.4.0

• Drop support for Python 3.5, which reached end-of-life in late 2020. Supported versions as of this release are 3.6 - 3.9
• Implement automatic board type detection (#32, @p1r473),
  passing a board_type to the constructor is no longer necessary in most cases, even when using an ASUS Tinker Board
• Fix setting brightness to max value and brightness fading loop condition (#35, @Martin-HiPi)