py-cryptodome: updated to 3.8.0

3.8.0:

New features
* Speed-up ECC performance. ECDSA is 33 times faster on the NIST P-256 curve.
* Added support for NIST P-384 and P-521 curves.
* EccKey has new methods size_in_bits() and size_in_bytes().
* Support HMAC-SHA224, HMAC-SHA256, HMAC-SHA384, and HMAC-SHA512 in PBE2/PBKDF2.

Resolved issues
* DER objects were not rejected if their length field had a leading zero.
* Allow legacy RC2 ciphers to have 40-bit keys.
* ASN.1 Object IDs did not allow the value 0 in the path.

Breaks in compatibility
* point_at_infinity() becomes an instance method for Crypto.PublicKey.ECC.EccKey, from a static one.

(adam)