squid: Update to 6.14

squid: Update to 6.14

For details see:
https://github.com/squid-cache/squid/releases/tag/SQUID_6_14

"Changes in squid-6.14 (24 Jun 2025):

- Bug 5352: Do not get stuck in RESPMOD after pausing peer read(2)
- Bug 5489: Fix "make check" linking on Solaris
- Fix SNMP cacheNumObjCount -- number of cached objects
- Do not duplicate received Surrogate-Capability in sent requests
- Fix Mem::Segment::open() stub to fix build without shm_open()
- ... and CI and documentation updates"

Signed-off-by: Matthias Fischer <matthias.fischer@ipfire.org>