- update to 0.19.0:
* `to_ssh` in `VerifyingKey` and `SigningKey`, supports Ed25519
keys only
* Support for twisted Brainpool curves
* Fix curve equation in glossary
* Documentation for signature encoding and signature decoding
functions
* Officially support Python 3.11 and 3.12
* Small updates to test suite to make it work with 3.11 and
3.12 and new releases of test dependencies
* Dropped the internal `_rwlock` module as it's unused
* Added mutation testing to CI, lots of speed-ups to the test
suite to make it happen
* Removal of unnecessary `six.b` literals (Alexandre Detiste)

order bit size and the curve order is not a multiple of 8