Fix URL encoding mismatch

[l4u23n7p]

Hello @carsonyl ,

Thanks for your work on this project, it has been really helpful in corporate environment.

I opened this PR to fix a bug in proxy authentication URL encoding.

PyPac uses quote_plus for encoding whereas requests uses unquote for decoding.

pypac/pypac/resolver.py

Lines 130 to 132 in 44fd400

	return "{0}://{1}:{2}@{3}".format(
	parsed.scheme, quote_plus(proxy_auth.username), quote_plus(proxy_auth.password), parsed.netloc
	)

https://github.com/psf/requests/blob/420d16bc7ef326f7b65f90e4644adc0f6a0e1d44/src/requests/utils.py#L1017.

It leads to space ( ) character not being decoded correctly on requests side, resulting in 407 proxy error.

I would highly appreciate this fix to be merged.

Regards,

[carsonyl]

Thanks!