dns/powerdns: update to 4.8.1

ChangeLog: https://blog.powerdns.com/2023/07/07/authoritative-server-4-8-1

New Features
 * lmdb: add backend commands for checking & refreshing indexes

Improvements
 * lmdb: in Lightning Stream mode, during deleteDomain, use RW transaction to
   get ID list
 * Stop using the now deprecated ERR_load_CRYPTO_strings() to detect OpenSSL
 * Work around Red Hat 8 pooping the bed in OpenSSL’s headers

Bug Fixes
 * YaHTTP: Prevent integer overflow on very large chunks

PR:		272476
Reported by:	tremere@cainites.net (maintainer)