Merge pull request #3530 from jupyterhub/update-image-requirements

hub image: refreeze requirements.txt

Author: minrk

images/singleuser-sample/requirements.txt

@@ -65,7 +65,7 @@ greenlet==3.1.1
     # via sqlalchemy
 h11==0.14.0
     # via httpcore
-httpcore==1.0.5
+httpcore==1.0.6
     # via httpx
 httpx==0.27.2
     # via jupyterlab