Requirements Version specification for pip > 24

[czackl]

With pip versions > 24 this requirement specification is not valid anymore so installation fails. Only older pip versions allow the installation of autogenes at the moment.

https://github.com/theislab/AutoGeneS/blob/22bde0d5eba013e90edb85341e0bd9c28b82e7fd/requirements.txt#L9