v0.4.2

Added

• tip releases are now available at stable URLs:
  • https://github.com/actonlang/acton/releases/download/tip/acton-darwin-x86_64.tar.bz2
  • https://github.com/actonlang/acton/releases/download/tip/acton-linux-x86_64.tar.bz2

Fixed

• versioned releases now use correct version number, like 0.4.1 rather than
  the version style used for tip releases which include the date & time, like
  0.4.1.2021.08.05.12.15.37
• tip release tar balls now reflect the full tip version in the filename
  • like acton-linux-x86_64-0.4.1.20210805.13.46.55.tar.bz2
  • previously, it would just be acton-linux-x86_64-0.4.1.tar.bz2, making it
    difficult to differentiate against the proper 0.4.1 or other nightlies