The job was canceled because "_7_2_5_6_16" failed.

Your requirements could not be resolved to an installable set of packages. Problem 1 - Root composer.json requires yiisoft/yii2 >=2.0.50 -> satisfiable by yiisoft/yii2[2.0.50]. - yiisoft/yii2 2.0.50 requires php >=7.3.0 -> your php version (5.6.40) does not satisfy that requirement.