Quoting (URL-encoding) Base authentication username / password is incorrect

[igielski]

Describe the bug

Version 1.3.0 introduces a change in the encoding of the Basic Authentication header (commit d2d1f49). In the comment to the commit you're mentioning this RFC section: https://datatracker.ietf.org/doc/html/rfc6749#section-2.3.1, but I think that rather this one is applicable:
https://datatracker.ietf.org/doc/html/rfc2617#section-2

I've never seen basic auth username and password being url encoded before. The servers (e.g. cloud foundry UAA) seem to reject such requests. It also doesn't make sense to url-encode it if it's then base64-encoded

Error Stacks

--

To Reproduce

A minimal example to reproduce the behavior:
happens always in version 1.3.0 if basic authentication is used to get a token.

Expected behavior

Basic authentication username and password shouldn't be URL encoded before being base64 encoded.

Environment:

• OS: Linux / Mac OSX
• Python Version: 3.11
• Authlib Version: 1.3.0

Additional context

--