blake2b/blake2s support (#3116)
* blake2b/blake2s support
Doesn't support keying, personalization, salting, or tree hashes so
the API is pretty simple right now.
* implement digest_size via utils.read_only_property
* un-keyed for spelling's sake
* test copying + digest_size checks
* unkeyed is too a word
* line wrap
* reword the docs
* use the evp algorithm name in the error
This will make BLAKE2 alternate digest size errors a bit less confusing
* add changelog entry and docs about supported digest_size
7 files changed