Test released versions, not dev

Author: davidbrochart

.github/workflows/downstream.yml

@@ -23,9 +23,7 @@ jobs:
         run: |
           pip install --upgrade pip
           pip install .
-          pip install pytest "nbclient[test] @ git+git://github.com/jupyter/nbclient.git@master" \
-                             "ipyparallel[test] @ git+git://github.com/ipython/ipyparallel.git@main" \
-                             jupyter_client[test] pytest-asyncio
+          pip install pytest nbclient[test] ipyparallel[test] jupyter_client[test] pytest-asyncio
           pip freeze
 
       - name: Run tests