Stick appveyor sbt version to 0.13
Stick appveyor sbt version to 0.13

olafurpg/scalafmt,scalameta/scalafmt,olafurpg/scalafmt,scalameta/scalafmt,olafurpg/scalafmt,scalameta/scalafmt,olafurpg/scalafmt,scalameta/scalafmt