Updates zend-session to ^2.8.1 for PHP 7.2 compatibility
Updates zend-session to ^2.8.1 for PHP 7.2 compatibility

zend-session 2.8.1 is the first that offers PHP 7.2 compabitibility, and
is thus the first version zend-view can rely on if it wants to provide
7.2 support.

This is a development dependency, so no minor bump is necessary.

zendframework/zend-view,zendframework/zend-view