syslog-ng: bump version in config file

syslog-ng: bump version in config file

This fixes issues:
syslog-ng[3895]: WARNING: Configuration file format is too old, syslog-ng is running in compatibility mode. Please update it to use the syslog-ng 3.29 format at your time of convenience. To upgrade the configuration, please review the warnings about incompatible changes printed by syslog-ng, and once completed change the @version header at the top of the configuration file; config-version='3.26'

Fixes: 06f3ac21b4d7be5a31f6739ab57e140260cdcd95 ("syslog-ng: update to
version 3.29.1")

Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>