Update login methods in package docs (#20561)

docs/content/doc/packages/container.en-us.md

@@ -34,6 +34,8 @@ To push an image or if the image is in a private registry, you have to authentic
 docker login gitea.example.com
 ```
 
+If you are using 2FA or OAuth use a [personal access token]({{< relref "doc/developers/api-usage.en-us.md#authentication" >}}) instead of the password.
+
 ## Image naming convention
 
 Images must follow this naming convention: