PHP dependency conflict: "psr/http-message" now requires PHP 7.2

[leoloso]

Cortex does not lock the required version of "psr/http-message":

{
  "require": {
    "psr/http-message": "*"
  }
}

This package released v2 requiring PHP 7.2, and it updated the signature of its methods to make use of PHP 7.2 features.

Now, when using Cortex with PHP 7.1, we get an error:

2023-04-08T08:15:22.016874876Z [Sat Apr 08 08:15:22.016525 2023] [php:error] [pid 1179] [client 172.19.0.2:59764] PHP Fatal error:  Declaration of Brain\\Cortex\\Uri\\PsrUri::getScheme() must be compatible with Psr\\Http\\Message\\UriInterface::getScheme(): string in /app/wordpress/wp-content/plugins/graphql-api/vendor/brain/cortex/src/Cortex/Uri/PsrUri.php on line 55

If Cortex were to still require PHP 5.5, I guess the best way to fix the issue is to lock the dependency to version 1.0.1, which is the last version on PHP 5.3.