declare versionScheme and enable MiMa

fixes #210

build.sbt

@@ -18,6 +18,9 @@ def osgiExport(scalaVersion: String, version: String) = {
   }) ++ Seq(s"scala.compat.java8.*;version=${version}")
 }
 
+ThisBuild / versionScheme := Some("early-semver")
+ThisBuild / versionPolicyIntention := Compatibility.BinaryAndSourceCompatible
+
 lazy val commonSettings = Seq(
   scalacOptions ++= Seq("-feature", "-deprecation", "-unchecked"),
 
@@ -70,7 +73,10 @@ lazy val scalaJava8Compat = (project in file("."))
 
     libraryDependencies += "com.novocode" % "junit-interface" % "0.11" % "test",
 
-    scalaModuleMimaPreviousVersion := None,
+    // we're still in 0.x land so we could choose to break bincompat,
+    // but let's at least be aware when we're doing it. also we should
+    // think about going 1.0, it's been a while
+    scalaModuleMimaPreviousVersion := Some("0.9.1"),
 
     testOptions += Tests.Argument(TestFrameworks.JUnit, "-v", "-a"),
 

build.sh

@@ -62,4 +62,4 @@ export CI_SNAPSHOT_RELEASE="publish"
 # for now, until we're confident in the new release scripts, just close the staging repo.
 export CI_SONATYPE_RELEASE="; sonatypePrepare; sonatypeBundleUpload; sonatypeClose"
 
-sbt "$setTagScalaVersion" clean test publishLocal $releaseTask
+sbt "$setTagScalaVersion" clean test versionPolicyCheck publishLocal $releaseTask

project/plugins.sbt

@@ -1 +1,2 @@
 addSbtPlugin("org.scala-lang.modules" % "sbt-scala-module" % "2.2.4")
+addSbtPlugin("ch.epfl.scala" % "sbt-version-policy" % "1.0.0-RC5")