Implement support for page equals null in pagination queries

[Kauto]

On my server I found the issue

Nuwave\Lighthouse\Pagination\PaginationArgs::__construct(): Argument #1 ($page) must be of type int, null given, called in /var/www/app/vendor/nuwave/lighthouse/src/Pagination/PaginationArgs.php on line 55 {"exception":"[object] (TypeError(code: 0): Nuwave\\Lighthouse\\Pagination\\PaginationArgs::__construct(): Argument #1 ($page) must be of type int, null given, called in /var/www/app/vendor/nuwave/lighthouse/src/Pagination/PaginationArgs.php on line 55 at /var/www/app/vendor/nuwave/lighthouse/src/Pagination/PaginationArgs.php:18)
[stacktrace]
#0 /var/www/app/vendor/nuwave/lighthouse/src/Pagination/PaginationArgs.php(55): Nuwave\\Lighthouse\\Pagination\\PaginationArgs->__construct()
#1 /var/www/app/vendor/nuwave/lighthouse/src/Pagination/PaginateDirective.php(140): Nuwave\\Lighthouse\\Pagination\\PaginationArgs::extractArgs()

I wrote a test to reproduce the error and fixed it.

• Added or updated tests
• Documented user facing changes
• Updated CHANGELOG.md

Changes

When explicit setting page to null in a pagination query, page is set to 1.

[spawnia]

Thank you, released with https://github.com/nuwave/lighthouse/releases/tag/v6.64.1