dns/dnsdist: update to 1.8.2
https://dnsdist.org/changelog.html#change-1.8.2
This release fixes the HTTP2 rapid reset attack, and requires
the updated libh2o fix.
Security: CVE-2023-44487
(cherry picked from commit 7710d75e67bc4e24985d7a81066a7e086e49bb69)