Update JWT / fetch through through composer

The version of JWT in the repository is rather old (unknown version from 2017).

If would be great if this could be updated to a more recent version to avoid conflicts with other apps that use a more recent version of JWT (https://github.com/nextcloud/spreed/pull/7372 being an example). The call arguments of JWT::sign have changed in that the algorithm is now mandatory.

Another possibility would be to use composer to track the dependency and automatically get notified about updates (e.g. through dependabot or renovate).