New release including `sklearn`->`scikit-learn` update

Hi!
In order for the update to `requirements.txt` file made in https://github.com/eth-cscs/abcpy/commit/caf0fd899424da69c0ef0bcd499696c5a077cdb1 to take effect for `pip` users, a new version of `abcpy` has to be released to PyPI. Would it be possible to release such a version? Thanks in advance!