Update plotly in blog posts for Colab

[MaxGhenis]

Running https://colab.research.google.com/github/UBICenter/blog/blob/master/jb/20200707/adult_child_ubi.ipynb shows this error. I think it's because it's running an old version of plotly, so Colab notebooks should update plotly. cc @ngpsu22

ValueError                                Traceback (most recent call last)
<ipython-input-1-c893d11fa016> in <module>()
    201            title='Overall poverty rate and spending on cash transfer programs',
    202            xaxis_title='Spending in billions',
--> 203            yaxis_title='SPM poverty rate')

4 frames
/usr/local/lib/python3.6/dist-packages/plotly/basedatatypes.py in _raise_on_invalid_property_error(self, *args)
   3664                     full_obj_name=full_obj_name,
   3665                     invalid_str=invalid_str,
-> 3666                     prop_descriptions=self._prop_descriptions,
   3667                 )
   3668             )

ValueError: Invalid property specified for object of type plotly.graph_objs.Layout: 'legend_title_text'

[MaxGhenis]

Unfortunately it doesn't look like there's a way to update packages and have the notebook run smoothly from there, since the runtime needs to be restarted for the new package to be recognized. The closest possible is to have this code block at the beginning (fully hidden in jupyter-book) and then have users follow instructions in restarting after upgrading plotly:

import plotly
if plotly.__version__ < '4.8':
    !pip install --upgrade plotly
    print('Plotly upgraded! Now Runtime...Restart and run all.')
    import os
    os.kill(os.getpid(), 9)  # Kills Python to force a restart.

I confirmed that the blog post works fine after running this.