Missing JWT expiration response schema related to dj rest auth

[huynguyengl99]

Hi, I've noticed an issue with the JWT token response in the rest_auth package's contrib module, where the schema is missing the expiration information. To address this, I've created a pull request to update the schema: #1149. This is my first contribution to updating this package. If there are any steps in the workflow that I've overlooked, please let me know so I can make the necessary adjustments.

(Thank you for developing this great package.)

[huynguyengl99]

Hi @tfranzel, do I miss any works/codes for the mentioned PR to be accepted? I just want to contribute a little effort to this great package 😄.