Remove dns_v4_first directive from squid.conf

dns_v4_first is obsoleted after squid v4 [1]. Notes on the
deprecation of dns_v4_first say: "Instead of obeying dns_v4_first
settings, IP family usage order is now primarily controlled by DNS
response time: If a DNS AAAA response comes first while Squid is
waiting for an IP address, then Squid will use the received IPv6
address(es) first."

[1] https://www.squid-cache.org/Doc/config/dns_v4_first/

Author: m-bull

etc/kayobe/containers/squid_proxy/squid.conf

@@ -78,6 +78,3 @@ refresh_pattern ^gopher:	1440	0%	1440
 refresh_pattern -i (/cgi-bin/|\?) 0	0%	0
 refresh_pattern .		0	20%	4320
 
-# Disable connections over IPv6
-# https://ramesh-sahoo.medium.com/squid-proxy-server-has-stopped-handling-connection-resulting-in-none-503-0-connect-errors-55477316850a
-dns_v4_first on