Key Error when decoding DER signatures on P521 curve

Hello,

There is a key error when decoding the encoded signature using the P521-curve.

'''
    Generating Keys
'''

from fastecdsa import keys, curve, ecdsa

priv_key,pub_key = keys.gen_keypair(curve.P521)

'''
    Signing and verifyng
'''
m = "Hello World"

r,s = ecdsa.sign(m,priv_key,curve=curve.P521)
valid = ecdsa.verify((r,s),m,pub_key,curve=curve.P521)

'''
    Encoding signatures
'''

from fastecdsa.encoding.der import DEREncoder

encoded = DEREncoder.encode_signature(r,s)
decoded_r, decoded_s = DEREncoder.decode_signature(encoded)

print(decoded_r)

[pcece]

I forgot to stress that I have tested the signature computation ECDSA NIST-P521 SHA2-512 with FIPS-186-4 test vectors and everything was OK. So thank you very much for this great library and this great work.

[AntonKueltz]

Fixed in 7fd41568eacc745811801396157b5672eb5789a4, will be in release v2.1.1.

   ...: '''
   ...:     Signing and verifyng
   ...: '''
   ...: m = "Hello World"
   ...:
   ...: r,s = ecdsa.sign(m,priv_key,curve=curve.P521)
   ...: valid = ecdsa.verify((r,s),m,pub_key,curve=curve.P521)
   ...:
   ...: '''
   ...:     Encoding signatures
   ...: '''
   ...:
   ...: from fastecdsa.encoding.der import DEREncoder
   ...:
   ...: encoded = DEREncoder.encode_signature(r,s)
   ...: decoded_r, decoded_s = DEREncoder.decode_signature(encoded)
   ...:
   ...: print(r == decoded_r, s == decoded_s)
True True