Git caching

This improvement will cache

https://git.noc.ruhr-uni-bochum.de/potentials-workshop-2022/workshop_preparation.git into /srv/conda/envs/notebook/workshop-repo-cache/workshop_preparation

and

https://github.com/pyiron/pyiron-resources.git into /srv/conda/envs/notebook/workshop-repo-cache/pyiron-resources