%store -r won't work without pickleshare installed

[kisunji]

IPython made pickleshare optional in this PR, so users may be unable to fetch stored variables across ipynb files.

/home/ckim/.local/lib/python3.10/site-packages/IPython/extensions/storemagic.py:229: UserWarning: This is now an optional IPython functionality, setting autorestore/API_KEY requires you to install the `pickleshare` library.
  db[ 'autorestore/' + arg ] = obj
/home/ckim/.local/lib/python3.10/site-packages/IPython/extensions/storemagic.py:229: UserWarning: This is now an optional IPython functionality, setting autorestore/MODEL_NAME requires you to install the `pickleshare` library.
  db[ 'autorestore/' + arg ] = obj