get admin/scalafmt.sh working again (#375)

recently this started failing on Travis-CI

note that the scalafmt version we're using is antiquated and doesn't
like trailing commas in build.sbt.  I didn't attempt an upgrade

Author: SethTisue

admin/scalafmt.sh

@@ -8,7 +8,9 @@ COURSIER="$HERE/.coursier"
 SCALAFMT="$HERE/.scalafmt-$VERSION"
 
 if [ ! -f $COURSIER ]; then
-  curl -L -o $COURSIER https://git.io/vgvpD
+  # note that the launch script we're using here is considered antiquated and was removed by
+  # https://github.com/coursier/coursier/pull/1565
+  curl -L -o $COURSIER 'https://github.com/coursier/coursier/blob/483c980e784cf33168be94cfc1e5682f56d71142/coursier?raw=true'
   chmod +x $COURSIER
 fi
 

build.sbt

@@ -74,7 +74,7 @@ lazy val compat = MultiScalaCrossProject(JSPlatform, JVMPlatform, NativePlatform
         import com.typesafe.tools.mima.core._
         import com.typesafe.tools.mima.core.ProblemFilters._
         Seq(
-          exclude[ReversedMissingMethodProblem]("scala.collection.compat.PackageShared.*"), // it's package-private
+          exclude[ReversedMissingMethodProblem]("scala.collection.compat.PackageShared.*") // it's package-private
         )
       },
     )