0.6.4.0

Improvements:

• spago init will search for a psc-package.json, and try to port it to your new spago.dhall config (#76)
• Add the spacchetti-upgrade command, to automatically upgrade to the latest Package Set (#93, #73)
• You can now add local packages to the Package Set 🎉 (#96, #88)
• Now it's possible to run spago install foo bar to add new dependencies to your project (#74, thanks @btrepp!)
• Now every time you try to build, Spago will also check that dependencies are installed (#75, #82)

Bugfixes:

• Spago would crash if $HOME was not set, now it doesn't anymore (#85, #90)
• spago test now actually works on Windows (#79, thanks @btrepp!)

Other:

• Maany docs improvements (#83, #76, #93, #96, #99, #100)
• From this release we are publishing an experimental Windows build (#81)
• Add a PR checklista, so we don't forgetti (#86)