stream_filter_append use mixed instead of array

[ildyria]

https://www.php.net/manual/en/function.stream-filter-append.php Defines stream_filter_append as :

stream_filter_append(
    resource $stream,
    string $filtername,
    int $read_write = ?,
    [mixed](https://www.php.net/manual/en/language.types.declarations.php#language.types.declarations.mixed) $params = ?
): resource

This PR aims to fix the inconsistency as here $params is defined as array.

PS: Tried to run the scripts, it crashed with:

sh: 1: exec: vendor/bin/phpcbf: not found
Editing composer.json