Use an import instead of compat traits.

Author: mrdziuban

sbt-plugin/build.sbt

@@ -43,9 +43,11 @@ val `sbt-github-dependency-submission` = project
       "UTF-8",
       "-feature",
       "-unchecked",
-      "-Xfatal-warnings",
-      "-Ywarn-unused-import"
-    ),
+      "-Xfatal-warnings"
+    ) ++ (scalaBinaryVersion.value match {
+      case "2.12" => Seq("-Ywarn-unused-import")
+      case _ => Seq("-Wunused:imports")
+    }),
     libraryDependencies ++= Seq(
       "com.eed3si9n" %% "gigahorse-asynchttpclient" % "0.7.0",
       "org.scalameta" %% "munit" % "1.1.0" % Test

sbt-plugin/src/main/scala-2/ch/epfl/scala/GithubDependencyGraphPlugin.scala

@@ -13,7 +13,11 @@ import sbt.internal.util.complete.Parsers
 import sbt.plugins.JvmPlugin
 import sjsonnew.shaded.scalajson.ast.unsafe.JString
 
-object GithubDependencyGraphPlugin extends AutoPlugin with GithubDependencyGraphPluginCompat {
+// `import sbt.Result._` is unused in Scala 2/sbt 1 but necessary in Scala 3/sbt 2
+@annotation.nowarn("msg=Unused import")
+object GithubDependencyGraphPlugin extends AutoPlugin {
+  import sbt.Result._
+
   private val runtimeConfigs =
     Set(
       Compile,