Permission denied issue

[Robinlovelace]

Hi @karthik, many thanks for a great package! I'm having issues with the latest version though, I see this message after launching the binder instance associated with this commit: https://github.com/Robinlovelace/geocompr/commit/5a66c712a5f936f5bb123d1305e7f7a64c84e9d2

FROM rocker/binder:4.0.2
LABEL maintainer='Robin Lovelace'
USER root
COPY . ${HOME}
RUN chown -R ${NB_USER} ${HOME}
USER ${NB_USER}

Reproducible example (assuming I've not updated the .binder/Dockerfile since then): https://mybinder.org/v2/gh/robinlovelace/geocompr/master?urlpath=rstudio