build-contexts input

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

.github/workflows/ci.yml

@@ -388,6 +388,27 @@ jobs:
             docker:10.180.0.1
             foo:10.0.0.1
 
+  build-contexts:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v2
+      -
+        name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+        with:
+          version: v0.8.0
+      -
+        name: Build
+        uses: ./
+        with:
+          context: ./test
+          file: ./test/buildcontext.Dockerfile
+          build-contexts: |
+            alpine=docker-image://debian:stable-slim
+          tags: name/app:latest
+
   multi:
     runs-on: ubuntu-latest
     strategy: