Git GPG signatures can have non-ascii characters

Some Git commits have non-ascii characters in the GPG signature:

b'-----BEGIN PGP SIGNATURE-----\nComment: \xe2\x98\x83\xc2\xa0\xd0\xa6\xce\xa4\xe2\x84\xb1\xe2\x80\x94\xef\xbc\x98\xe3\x80\x80\xe2\x98\x95\xe2\x98\x82\xe2\x98\x84\n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\nNMJjgLv8feTqjf62m94l\n=NTe8\n-----END PGP SIGNATURE-----'