Fix issues for python > 3.7

[abelhOrihuela]

No description provided.

[ianlintner-wf]

For user examples it's always tricky just providing version changes... def not saying this is the RIGHT way just a couple other options.

Option 1:

import sys
if sys.version_info.major > 2:  # Python 3 or later
    from urllib.parse import quote
else:  # Python 2
    from urllib import quote

Option 2:

use pip install six
since the code already has pip dependency for jwt

Suggested change

	import urllib
	from six.moves.urllib.parse import quote

#Then change line 39 to

quote(return_to)

If not I would make the python3 version the default.

[ianlintner-wf]

In tandem with above addition of import

Suggested change

	# sso_url += "&return_to=" + urllib.parse.quote(return_to)
	sso_url += "&return_to=" + urllib.quote(return_to)
	sso_url += "&return_to=" + quote(return_to)