Comment 5 for bug 1643256

Revision 47 on the 3.2 branch adds a helpful syntax error if you try to run any Beautiful Soup 3 code under Python 3, and a discontinuation warning for everyone else.

I've set the cutoff date to January 1, 2021, one year after the discontinuation date for Python 2 itself. At some point after that I'll reclaim the 'beautifulsoup' package name on pip by changing it to a more recent version.