remove binder test from stage workflow

(has now specific workflow)

Author: fangohr

.github/workflows/stage.yml

@@ -50,23 +50,6 @@ jobs:
         make docker-pdf
         sudo cp book/_build/latex/book.pdf book/_build/html/book.pdf
 
-  repo2docker-build-and-test:
-    runs-on: ubuntu-latest
-    steps:
-    - uses: actions/checkout@v2
-
-    - name: Build Docker Container with repo2docker
-      uses: jupyterhub/repo2docker-action@master
-      with:
-        NO_PUSH: 'true'
-        IMAGE_NAME: "python4compscience-binder"
-
-    - name: List Available Images
-      run: docker images
-
-    - name: Test with nbval
-      run: make docker-binder-nbval
-
 #     - name: Publish
 #       uses: netlify/actions/build@master
 #       env: