add Scala 3 to crossbuild#215

Merged

SethTisue merged 7 commits intoscala:mainfrom

SethTisue:scala3

Mar 29, 2021

Commits on Mar 23, 2021

sbt build cleanup: use slash syntax
SethTisue
committed

Commits on Mar 25, 2021

avoid deprecation warning
SethTisue
committed