remove donwstream check (#413)

Author: Carreau

.github/workflows/downstream.yml

@@ -80,19 +80,3 @@ jobs:
         with:
           package_name: pytest_jupyter
           package_spec: pip install -e ".[test,client,server]"
-
-  downstreams_check: # This job does nothing and is only used for the branch protection
-    if: always()
-    needs:
-      - ipykernel
-      - nbclient
-      - nbconvert
-      - jupyter_server
-      - jupyter_client
-      - pytest_jupyter
-    runs-on: ubuntu-latest
-    steps:
-      - name: Decide whether the needed jobs succeeded or failed
-        uses: re-actors/alls-green@release/v1
-        with:
-          jobs: ${{ toJSON(needs) }}