update composer.json for Magento 2.3 compatibility

[kgerasimov]

As I see, the code itself is fully compatible with Magento 2.3.x, however composer declaration requires 2.2.x versions of dependencies:

    "magento/module-store": "100.2.*",
    "magento/module-customer": "101.0.*",
    "magento/module-authorization": "100.2.*",
    "magento/module-checkout": "100.2.*",
    "magento/module-backend": "100.2.*",
    "magento/module-eav": "101.0.*",
    "magento/module-config": "101.0.*",
    "magento/framework": "101.0.*",
    "magento/module-quote": "101.0.*"