raise dependency on PHP 8.0

keep compatibility using laminas-zendframework-bridge
  as this is only used using compat autolader
raise dependency on laminas-config 3.7
raise dependency on laminas-eventmanager 3.4
raise dependency on laminas-stdlib 3.3

raise dependency on PHP 7.3
add dependency on brick/varexporter
raise dependency on laminas/laminas-config 3.4
raise dependency on laminas/laminas-eventmanager 3.3
raise dependency on laminas/laminas-stdlib 3.3
raise dependency on laminas/laminas-zendframework-bridge 1.1
switch to phpunit 9.3

add dependency on webimpress/safe-writer

bootstrap build without laminas-mvc