contrib/hgweb.wsgi

sslutil: drop support for Python prior to 3.7

There's also a block of code around line 47 related to `ssl.HAS_TLSv1` to
determine the supported protocols that references "Python 3.7", but I'm not
altering that because the commit referenced there wasn't landed until just prior
to the 3.9 release, and I'm not sure what flavors of py38 might not have a
backport.

Avoid de-indenting for now for a clearer text diff.

# An example WSGI for use with mod_wsgi, edit as necessary
# See https://mercurial-scm.org/wiki/modwsgi for more information

# Path to repo or hgweb config to serve (see 'hg help hgweb')
config = b"/path/to/repo/or/config"

# Uncomment and adjust if Mercurial is not installed system-wide
# (consult "installed modules" path from 'hg debuginstall'):
#import sys; sys.path.insert(0, "/path/to/python/lib")

# enable demandloading to reduce startup time
from mercurial import demandimport; demandimport.enable()

from mercurial.hgweb import hgweb
application = hgweb(config)