Add migrated GitHub workflow

.github/workflows/test.yml

@@ -0,0 +1,24 @@
+---
+on: push
+name: Test
+jobs:
+  test:
+    name: Run tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@master
+
+      - name: Dockerfilelint
+        uses: docker://replicated/dockerfilelint
+        with:
+          args: Dockerfile
+
+      - name: Bats
+        uses: actions/bin/bats@master
+        with:
+          args: test/*.bats
+
+      - name: ShellCheck
+        uses: actions/bin/shellcheck@master
+        with:
+          args: entrypoint.sh