bump scl submodule to v2.3.0
bump scl submodule to v2.3.0

Among other changes this drops support for syslog-ng 3.2 and adds support for syslog-ng 3.4.

talis/puppet-syslogng,talis/puppet-syslogng,purplehazech/puppet-syslogng,omarqureshi/puppet-syslogng,purplehazech/puppet-syslogng,omarqureshi/puppet-syslogng,Elefrancois/puppet-syslogng,Elefrancois/puppet-syslogng