Fix PHP version constraint in composer.json

[versusbassz]

Usually, packages require PHP version in require section of composer.json
Probably, config -> platform -> php is not enough.

Examples

• https://github.com/laravel/laravel/blob/8.x/composer.json#L8
• https://github.com/symfony/var-dumper/blob/5.4/composer.json#L19
• upd: the example of usage of both (require and config) settings: https://github.com/symfony/demo/blob/main/composer.json

Links

• https://getcomposer.org/doc/04-schema.md#package-links
• https://getcomposer.org/doc/06-config.md#platform
• https://mikemadison.net/blog/2020/11/17/configuring-php-version-with-composer