Patch: Fix reading service banners from TLS-1.3-enabled hosts 🔗 link

Hi,

Andreas Oberritter analyzed and fixed the well known and often
discussed issue with pop3s/imaps flapping in combination with TLS 1.3.
See https://bugs.debian.org/930532 and
https://salsa.debian.org/debian/xymon/-/merge_requests/1

I use this patch for many months now without any issues, so I'd like
to see it applied in the official code.

His patch is appended to this mail.

Greetings
Roland