Scala steward+1432 - Update scalatest to 3.1.2 (bp #1441) (#1442)

* Update scalatest to 3.1.2 (#1441)

Co-authored-by: Scala Steward <me@scala-steward.org>
Co-authored-by: Scala Steward <43047562+scala-steward@users.noreply.github.com>
(cherry picked from commit d65013c4

)

# Conflicts:
#	build.sbt
#	build.sc

* Fix broken merge

Co-authored-by: Jim Lawson <ucbjrl@berkeley.edu>