Replace callable with Closure
Replace callable with Closure

Aiming to restrict the amount of types handled by that method, this
reduces the parameter to a single type.

Users are able to use `Closure::fromCallable('doSomething')` or
`doSomething(...)` (PHP 8.1+) to use named functions as the source for
the customisation.

Signed-off-by: Luís Cobucci <7945d1712249176a02d684a84999e19c759a1347@gmail.com>

lcobucci/jwt