执行 composer install 或者 composer update 时遇到问题如下：
Your requirements could not be resolved to an installable set of packages.Problem 1- Installation request for doctrine/instantiator 1.0.3 -> satisfiable by doctrine/instantiator[1.0.3].- doctrine/instantiator 1.0.3 requires php ~5.3 -> your PHP version (7.0.3) does not satisfy that requirement.Problem 2- doctrine/instantiator 1.0.3 requires php ~5.3 -> your PHP version (7.0.3) does not satisfy that requirement.- phpunit/phpunit-mock-objects 2.3.0 requires doctrine/instantiator ~1.0,>=1.0.1 -> satisfiable by doctrine/instantiator[1.0.3].- Installation request for phpunit/phpunit-mock-objects 2.3.0 -> satisfiable by phpunit/phpunit-mock-objects[2.3.0].扩展对应 PHP 有些问题，这里可以设置 composer 忽略 PHP 的版本问题
composer install –ignore-platform-reqs
composer update –ignore-platform-reqs
