Bump version to 5.0.0-rc.1

Replace `TokenResponse` generic with associated type

This change slightly simplifies types throughout this crate by removing
a generic type parameter in many places that already have a generic type
representing a `TokenResponse`.

BREAKING CHANGES:
 - Removes `TT` type parameter from `TokenResponse` and
   `TokenIntrospectionResponse` traits trait and adds a `TokenType`
   associated type to each trait.
 - Removes (now-redundant) `TT` type parameter from `Client` and each
   `*Response` type

Bump http to 1.0 and reqwest to 0.12

BREAKING CHANGES: This changes several exported types, including
`HttpRequest` (`http::Request`) and `HttpResponse` (`http::Response`),
as well as the `reqwest` client (`reqwest::Client` and
`reqwest::blocking::Client`).

Resolves #237.

Fix curl mention in upgrade guide

Add MSRV to upgrade guide

Fix chrono WASM Cargo feature (#230)

Enable chrono `wasmbind` feature to fix panic in WASM environments.

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Co-authored-by: Truong Tan Dat <truongt@igbmc.fr>

Export device authorization flow types in top-level namespace

Previously, some of the types were exported at the top level, and
some were exported in the `devicecode` module, with no clear reason for
the separation. With this change, all related types are exported at
the top level, while the `devicecode` module continues to be exported
for backward compatibility.

Bump version to 4.4.0

Bump version to 4.3.0

Clean up docs