Pin multiprocess<0.70.1 to align with dill<0.3.9
The docs for this PR live [here](https://moon-ci-docs.huggingface.co/docs/datasets/pr_7188). All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.
Pin multiprocess<0.70.1 to align with dill<0.3.9.

Note that multiprocess-0.70.1 requires dill-0.3.9: https://github.com/uqfoundation/multiprocess/releases/tag/0.70.17

Fix #7186.