Merge pull request #889 from DuendeSoftware/pg/remove-preview-note

ATM 4.0 has been released and is no longer in preview

Author: maartenba

src/content/docs/accesstokenmanagement/index.mdx

@@ -16,11 +16,6 @@ The `Duende.AccessTokenManagement` library provides automatic access token manag
 - Automatic access token lifetime management using a refresh token for API calls on behalf of the currently logged-in user (using the `Duende.AccessTokenManagement.OpenIdConnect` package)
 - Revocation of access tokens
 
-:::note[Duende.AccessTokenManagement version 4 preview]
-Duende.AccessTokenManagement version 4 (preview) brings significant improvements, but also several breaking
-changes. Please see the [migration guide](/accesstokenmanagement/upgrading/atm-v3-to-v4.md) and [release notes](https://github.com/DuendeSoftware/foss/releases/tag/atm-4.0.0-Preview.2).
-:::
-
 ## Machine-To-Machine Token Management
 
 To get started, install the NuGet Package: