Default parameters can still raise MissingDependencyError

[sbischoff-ai]

Hi. The issue described in #31 and fixed in #40 still arises in some cases.

This:

import punq

class A:
    pass

class B:
    def __init__(self, a: A, x: int | None = None):
        pass

container = punq.Container()
container.register(A)
container.register(B)
container.resolve(B)

will still raise:

punq.MissingDependencyError: Failed to resolve implementation for int | None

(version 0.7.0)