add GitHub Actions, drop Travis-CI

.github/workflows/ci.yml

@@ -0,0 +1,25 @@
+name: test
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+jobs:
+  test:
+    strategy:
+      fail-fast: false
+      matrix:
+        java: [8, 11, 17]
+        scala: [2.13.6, 3.0.2]
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
+    - uses: coursier/cache-action@v6
+    - uses: actions/setup-java@v2
+      with:
+        distribution: adopt
+        java-version: ${{matrix.java}}
+    - name: Test
+      run: sbt ++${{matrix.scala}} test core/headerCheck package

.github/workflows/release.yml

@@ -0,0 +1,21 @@
+name: Release
+on:
+  push:
+    tags: ["*"]
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+      - uses: actions/setup-java@v2
+        with:
+          distribution: adopt
+          java-version: 8
+      - run: sbt versionCheck ci-release
+        env:
+          PGP_PASSPHRASE: ${{secrets.PGP_PASSPHRASE}}
+          PGP_SECRET: ${{secrets.PGP_SECRET}}
+          SONATYPE_PASSWORD: ${{secrets.SONATYPE_PASSWORD}}
+          SONATYPE_USERNAME: ${{secrets.SONATYPE_USERNAME}}

build.sbt

@@ -1,3 +1,17 @@
+ThisBuild / crossScalaVersions := Seq("2.13.6", "3.0.2")
+ThisBuild / scalaVersion := (ThisBuild / crossScalaVersions).value.head
+
+// shouldn't be necessary anymore after https://github.com/lampepfl/dotty/pull/13498
+// makes it into a release
+ThisBuild / libraryDependencySchemes += "org.scala-lang" %% "scala3-library" % "semver-spec"
+
+// this was necessary to get us from 3.0.0 to 3.0.2, but we should be able to remove
+// it after the next release
+import com.typesafe.tools.mima.core._
+ThisBuild / mimaBinaryIssueFilters ++= Seq(
+  ProblemFilters.exclude[IncompatibleSignatureProblem]("*"),
+)
+
 Global / cancelable := true
 publish / skip := true // in root
 

project/plugins.sbt

@@ -1 +1 @@
-addSbtPlugin("org.scala-lang.modules" % "sbt-scala-module" % "2.4.0")
+addSbtPlugin("org.scala-lang.modules" % "sbt-scala-module" % "3.0.0")