v2.4.0

• SOME BREAKING CHANGES. Modify the built-in sessions to support any kind
  of storage for the session information. It still defaults to storing sessions
  in cookies, but allows defining a custom SessionStore to store information
  where desired. Fix #542. Read the updated documentation on Sessions for more information.
• Remove charset-normalizer dependency. This library was used only when a
  UnicodeDecodeError exception occurred when parsing the body of a web
  request. This can happen in two circumstances: when the client sends a
  payload specifying the wrong encoding in the Content-Type request header,
  or when the client sends a payload that is not UTF-8 encoded and without
  specifying the charset encoding. Fix #581.
• Now the framework always returns Bad Request with a useful error message
  in the response payload, in the circumstances described in the point above.
• Correct bug in the parse_charset function that prevented proper parsing and
  optimal handling of input encodings different than UTF8. Parsing still
  worked in this case because of the automatic fallback to
  charset-normalizer.
• Correct the output of request.charset when the charset is obtained from the
  'Content-Type' request header.