Revert "actions: add docker-tests.yml"

This reverts commit d79c4524dc.

.github/workflows/docker-tests.yml

@@ -1,21 +0,0 @@
-name: Docker Image CI
-
-on:
-  push:
-    branches: [ main ]
-  pull_request:
-    branches: [ main ]
-
-jobs:
-
-  build:
-
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: actions/checkout@v2
-    - name: Build the Docker images
-      run: docker-tests/build-docker-images.sh
-    - name: Run the Docker tests
-      run: docker-tests/run-docker-tests.sh
-