Tests failure due to GPGME behavior change on gpgme_op_verify

[manphiz]

GPGME has now added "--verify" when invoking "gpg" which changed the behavior on gpgme_op_verify that results in gpg.Context.verify returning empty strings. See the Debian bug[1] for more details of the failure, and GPGME upstream bug[2] and commit[3] for more details of the GPGME change. This was done for GPGME 1.24.0 and backported to 1.23.2.

PGPy should update its tests to adapt to this new behavior.

[1] https://bugs.debian.org/1086378
[2] https://dev.gnupg.org/T6907
[3] https://dev.gnupg.org/rM1dc44b7c5b9253206af527721212d1f55532a7ee