Web.HTTP depend Python2, but Pyhon2 End of Life at 2020

[tsuyoshicho]

vital.vim/doc/vital/Web/HTTP.txt

Lines 87 to 91 in 9d093e2

	"client" Default: ["python", "curl", "wget"]
	Candidate list of HTTP client to use for a request.
	The first available one is used.
	A string as an HTTP client is also possible.
	See also |Vital.Web.HTTP-client|.

PEP 373 -- Python 2.7 Release Schedule | Python.org
Python 2.7 Countdown

Solution:
Python client prio down or rewrite to use Python3?