8.4 deprication notice

[ipranjal]

While using this library with 8.4 this library gives few deprication notice like

PHLAK\Config\Config::__construct(): Implicitly marking parameter $context as nullable is deprecated

on all the methods we need to add union type "|null" or mark parameter with "?" wherever we are explicitly setting it as null.

more detail can be found here https://php.watch/versions/8.4/implicitly-marking-parameter-type-nullable-deprecated

Not a critical issue , but good to take care of deprecation so that it is easier to move forward when newer versions come