New features
- Added support for HPKE (RFC 9180).
Resolved issues
- GH#812: CCM ciphers will now fail before encrypting (or decrypting)
data beyond the limit imposed by the nonce length. - GH#846: fix infinite loop with RC4 for data larger than 4GB.
- GH#852: handle correctly invalid PEM files with less than 3 lines.
Other changes
- Remove support for Python 3.6.