end
This exposes the data-requires-python field when the packages registers it.

cgi.escape() does not escape single quotes, so we need to make sure any
arguments parsed with cgi.escape() are wrapped with double quotes.

Using cgi.escape(quote=True) escapes double quotes. Though this is
unlikely to occur in a python_requires value, we want to protect against
double quote based sql injections.

The html parsing was separated into its own private function so that it
could be unit tested.