Fix JupyterLab Link Markdown

packages/hub-extension/README.md

@@ -1,6 +1,6 @@
 # @jupyterlab/hub-extension
 
-JupyterLab](https://github.com/jupyterlab/jupyterlab) integration for
+[JupyterLab](https://github.com/jupyterlab/jupyterlab) integration for
 [JupyterHub](https://github.com/jupyterhub/jupyterhub).
 
 This adds a "Hub" menu to JupyterLab that allows a user to log out of JupyterHub