Add option to provide SHA256 and SHA512 fingerprints.
Alternatively, extend existing --digest-algo option to change fingerprint output
format.
Probably it would be the best, to provide these in BASE64 instead of HEX format.
Example:
gpg --digest-algo SHA256 --fingerprint 0x12345678
...
Key fingerprint = 47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=