RFE: --version

[rcpao]

Please add --version to print the version and / or git hash of the built executable.

Motivation:
Copilot gave me a command line which included --out-cert:

• efikeygen --dbdir . --nickname nickname --common-name Custom_Kernel_Signing --out-cert mok.crt --out-key mok.key
  efikeygen: invalid argument: --out-cert: unknown option

I'm guessing SLES16 beta4 has a really old efikeygen.

$ efikeygen --version
efikeygen: invalid argument: --version: unknown option