test compile with github action

Author: niklasf

.github/workflows/test.yml

@@ -0,0 +1,13 @@
+name: Test
+
+on: [push, pull_request]
+
+jobs:
+  openjdk13:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions/setup-java@v1
+      with:
+        java-version: 13
+    - run: sbt compile