response header decoding depends on h2's version, need fix

[fflisguhcz04697]

header_encoding property of hyper-h2 changed in version 3.0.0: Changed default value from 'utf-8' to None, find in their document: https://python-hyper.org/projects/h2/en/stable/api.html.
So i think aioapns package should explicit set header_encoding property to None.