www/squid: Update 6.14 => 7.3

Changelogs:
https://github.com/squid-cache/squid/releases/tag/SQUID_7_0_1
https://github.com/squid-cache/squid/releases/tag/SQUID_7_0_2
https://github.com/squid-cache/squid/releases/tag/SQUID_7_1
https://github.com/squid-cache/squid/releases/tag/SQUID_7_2
https://github.com/squid-cache/squid/releases/tag/SQUID_7_3

PR: 290630