Proxy support

[mshow34jt]

given that urllib3 does not use proxy environment variables. would you consider adding code to detect and use a proxy?

for example:
I replaced "pm = urllib3.PoolManager(cert_reqs='CERT_NONE')" with

proxies_dict=urllib.request.getproxies()
if (proxies_dict):
try:
pm = urllib3.ProxyManager(proxies_dict["http"],cert_reqs='CERT_NONE')
except:
print(f"proxy set but not http")
quit()
else:
pm = urllib3.PoolManager(cert_reqs='CERT_NONE')

something like that.

Side note: timeouts might be nice too