Merge pull request flightphp#456 from jamalo/master

PHP 8.1: Type declare length as int

Merge branch 'master' of https://github.com/mikecao/flight

Merge pull request flightphp#395 from merkuriy/JsonSerializableCollec…

…tion

Added JsonSerializable for util/Collection

Merge pull request flightphp#409 from pluveto/patch-1

Trim url

Bump version.

Prevent response from sending more than once.

Fix conflict with external error handlers.

Response content-length header should use mbstring if available.

Removed another case of $route passing. Updated tests.

Remove $route from parameter list, only pass when dispatching callback.