PHPC-860: Add PHP versions 5.6-7.2 to matrix
PHPC-860: Add PHP versions 5.6-7.2 to matrix

mongodb/mongo-php-driver,mongodb-labs/mongo-php-driver-prototype,mongodb-labs/mongo-php-driver-prototype,derickr/mongo-php-driver,mongodb-labs/mongo-php-driver-prototype,mongodb/mongo-php-driver,jmikola/mongo-php-driver-prototype,jmikola/mongo-php-driver,jmikola/mongo-php-driver-prototype,derickr/mongo-php-driver-prototype,derickr/mongo-php-driver-prototype,derickr/mongo-php-driver-prototype,jmikola/mongo-php-driver-prototype,mongodb-labs/mongo-php-driver-prototype,jmikola/mongo-php-driver-prototype,jmikola/mongo-php-driver,jmikola/mongo-php-driver,derickr/mongo-php-driver,mongodb/mongo-php-driver,jmikola/mongo-php-driver,derickr/mongo-php-driver,derickr/mongo-php-driver-prototype,jmikola/mongo-php-driver-prototype,mongodb-labs/mongo-php-driver-prototype,jmikola/mongo-php-driver,mongodb/mongo-php-driver,mongodb/mongo-php-driver,derickr/mongo-php-driver,derickr/mongo-php-driver,derickr/mongo-php-driver,derickr/mongo-php-driver-prototype