add test workflow

see #59

Author: Kevin Buchholz

.github/workflows/testImageBuild.yml

@@ -0,0 +1,27 @@
+name: Build test image
+
+on: [pull_request]
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v2
+      -
+        name: Set up QEMU
+        uses: docker/setup-qemu-action@v1
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+      -
+        name: Build and push
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64
+          push: false
+          tags: |
+            sourceboat/docker-laravel:test
+            ghcr.io/sourceboat/docker-laravel:test