HMAC 384 and HMAC 512 keys are not supported

[LeviSchuck]

In pycose/keys/symmetric.py, there are several checks on key length which exclude keys for HS384 and HS512 algorithms.

if key_len not in [16, 24, 32]:

Here's how I reproduce this issue

from pycose.keys import SymmetricKey, keyops
from pycose.algorithms import HMAC256, HMAC384, HMAC512
from binascii import hexlify
hashes = [
    ["HS256", HMAC256],
    ["HS384", HMAC384],
    ["HS512", HMAC512]
]

for [name, alg] in hashes:
    print(f"{alg} - {alg.get_digest_length()}")
    key = SymmetricKey.generate_key(alg.get_digest_length())
    key.kid = b"[email protected]"
    key.key_ops = [keyops.MacCreateOp, keyops.MacVerifyOp]
    key.alg = alg
    print(hexlify(key.encode()))

This may be corrected by updating said list to

if key_len not in [16, 24, 32, 48, 64]:

Other implementations do support this length, for example in rust: https://github.com/tramires/cose-rust/blob/main/src/algs.rs#L1006