docs: updated readme
docs: updated readme

2600hz/kazoo-php-sdk,dhdanno/kazoo-php-sdk,voxter/kazoo-php-sdk,2600hz/kazoo-php-sdk,voxter/kazoo-php-sdk,2600hz/kazoo-php-sdk,dhdanno/kazoo-php-sdk,siplabs/kazoo-php-sdk,siplabs/kazoo-php-sdk