Magento 2.2. compatibility

[Tjitse-E]

• Removed Magento 2.2 constraint in composer.json
• Removed support for PHP 5.6, because of type hint change
• Fixed M2.2 DI compilation errors:

	PHPCuong\Faq\Model\ResourceModel\Faq\Grid\Collection
		Incompatible argument type: Required type: \Magento\Framework\DB\Adapter\AdapterInterface. Actual type: \PHPCuong\Faq\Model\ResourceModel\Faq\Grid\connection; File:
/vendor/php-cuong/magento2-faqs-extensions/Model/ResourceModel/Faq/Grid/Collection.php

	PHPCuong\Faq\Model\ResourceModel\Faqcat\Grid\Collection
		Incompatible argument type: Required type: \Magento\Framework\DB\Adapter\AdapterInterface. Actual type: \PHPCuong\Faq\Model\ResourceModel\Faqcat\Grid\connection; File:
/vendor/php-cuong/magento2-faqs-extensions/Model/ResourceModel/Faqcat/Grid/Collection.php

	PHPCuong\Faq\Model\ResourceModel\Faqcat
		Incompatible argument type: Required type: string. Actual type: \PHPCuong\Faq\Model\ResourceModel\connectionName; File:
/vendor/php-cuong/magento2-faqs-extensions/Model/ResourceModel/Faqcat.php

Total Errors Count: 3


  [Magento\Framework\Validator\Exception]
  Error during compilation

[samoudi2006]

Good
thank you

[danslo]

@Tjitse-E Another good idea here would be to remove the 'version' part in composer.json. It's not needed when properly using tags (which this repository is doing).