drop dependency on cakephp/collection

add dependency on psr/container

raise dependency on PHP 7.2
switch to cakephp v4
switch to phpunit v8

- raise dependency on cake 3.7

- allow Symfony 5

- raise dependency on symfony 3.4
- use phpunit 7

drop patch merged upstream
raise dependency on PHP 5.6
add dependency on cakephp/collection
add dependency on cakephp/database
use range dependencies on F27+

open https://github.com/cakephp/phinx/pull/1278 fix tests
use phpunit6 on Fedora
allow Symfony 4