Run testsuite on pushes to 5.x branch too.
Run testsuite on pushes to 5.x branch too.

Helpful when doing 4.next => 5.x merges.
cakephp/cakephp,cakephp/cakephp,cakephp/cakephp,CakeDC/cakephp,ADmad/cakephp,ADmad/cakephp,CakeDC/cakephp,ndm2/cakephp,ADmad/cakephp,CakeDC/cakephp,CakeDC/cakephp,cakephp/cakephp,ndm2/cakephp,ndm2/cakephp,ADmad/cakephp,ndm2/cakephp