Change Log

changes in 1.3

update scalastix-1.1, scala-2.13.3, sbt-1.3.13

changes in 1.2

update scala, sbt

changes in 1.1

update scala-2.12.4 and other project dependencies
update to latest scalastix-0.7, hence changed circe dependency to play.json
compatibility with STIX-2.0
code cleaning