Use local Docker registry in GitHub Action

The tests container copies files from the build containers. In order for
this to work in the GitHub actions workflow, the build images need to be
uploaded to a local Docker registry first.

.github/workflows/build-and-test.yml

@@ -9,36 +9,48 @@ jobs:
   build-and-test:
     name: Build curl-impersonate and run the tests
     runs-on: ubuntu-latest
+    services:
+      # A local registry is needed to push the build images to because we use
+      # the 'docker-container' driver. See
+      # https://github.com/docker/buildx/issues/301
+      # and
+      # See https://github.com/docker/build-push-action/blob/master/docs/advanced/local-registry.md
+      registry:
+        image: registry:2
+        ports:
+          - 5000:5000
     steps:
       - name: Check out the repo
         uses: actions/checkout@v2
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v1
+        with:
+          driver-opts: network=host
 
       - name: Build the Chrome version of curl-impersonate
         uses: docker/build-push-action@v2
         with:
-          push: false
-          load: true
+          push: true
           context: chrome/
-          tags: curl-impersonate-chrome:latest
+          tags: localhost:5000/curl-impersonate/chrome
 
       - name: Build the Firefox version of curl-impersonate
         uses: docker/build-push-action@v2
         with:
-          push: false
-          load: true
+          push: true
           context: firefox/
-          tags: curl-impersonate-firefox:latest
+          tags: localhost:5000/curl-impersonate/ff
 
       - name: Build the tests container
         uses: docker/build-push-action@v2
         with:
-          push: false
           load: true
           context: tests/
           tags: curl-impersonate-tests:latest
+          build-args: |
+            FIREFOX_IMAGE=localhost:5000/curl-impersonate/ff
+            CHROME_IMAGE=localhost:5000/curl-impersonate/chrome
 
       - name: Run the tests
         run: docker run --rm curl-impersonate-tests --log-cli-level DEBUG