Allowed arguments of SLURM option --get-user-env in SLURM v25.05

### Bug description

We are getting the following error after upgrading SLURM from v24.05 to v25.05.

```
sbatch: option '--get-user-env' doesn't allow an argument
```

The changes are mentioned in [slurm v25.05 changelog](https://github.com/SchedMD/slurm/blob/slurm-25.05/CHANGELOG/slurm-25.05.md): _Deprecate "GetEnvTimeout" from slurm.conf and "timeout" and "mode" optional parameters from sbatch's --get-user-env option. The default timeout to get the user environment will be 120 seconds._

And may be related to this [slurm f6d148 commit](https://github.com/SchedMD/slurm/commit/f6d1487fec88bdb4f04b9c987bc5cf46f45bd6f8).

### How to reproduce

1. use batchspawner with slurm 25.05 (released: May-June 2025)

### Your personal set up

- batchspawner 1.1.0dev0 or 1.3.0
- sbatch version: slurm 25.05.0
- OS: Rocky Linux 8.10 or CentOS 7.9.2009