raise dependency on PHP 8.0

drop dependency on container-interop/container-interop
add dependency on laminas/laminas-servicemanager
add dependency on psr/container

raise dependency on PHP 7.3

keep compatibility using laminas-zendframework-bridge
  as this is only used using compat autolader

raise dependency on laminas-math 3.4
raise dependency on laminas-stdlib 3.6

raise dependency on PHP 7.3
switch to phpunit9