- skip set -x and fix version update changes entry

- Update to 3.3.3
* When the master daemon runs with PID=1 (init mode), it will now
reap child processes from non-Postfix code running in the same
container, instead of terminating with a panic.
* Bugfix (introduced: postfix-2.11): with posttls-finger,
connections to unix-domain servers always resulted in "Failed
to establish session" even after a connection was established.
Jaroslav Skarva. File: posttls-finger/posttls-finger.c.
* Bugfix (introduced: Postfix 3.0): with smtputf8_enable=yes,
table lookups could casefold the search string when searching
a lookup table that does not use fixed-string keys (regexp,
pcre, tcp, etc.). Historically, Postfix would not case-fold
the search string with such tables. File: util/dict_utf8.c.

- PostrgeSQL's pg_config is meant for linking server extensions,
use libpq's pkg-config instead, if available.
This is needed to fix build with PostgreSQL 11.