Florian Wolf

For an even number of atoms, the calculation of ``self._a_values`` (see [here](https://github.com/MushroomRL/mushroom-rl/blob/649eefeefdcec49bdf4beacd3b06e85ebd8bce90/mushroom_rl/algorithms/value/dqn/categorical_dqn.py#L36)) does not seem to be 100% correct. This behavior is reproducible via ```python import torch v_min = -5...