Update R to 4.0

For an Ubuntu 18.04 base image, you can use the following instructions to upgrade R version to 4.0. The instructions remove the old R version, install R 4.0 and upgrades all the R packages. Add these to "Dockerfile Instructions" in your compute environment

RUN apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E298A3A825C0D65DFD57CBB651716619E084DAB9 && \
add-apt-repository 'deb https://cloud.r-project.org/bin/linux/ubuntu bionic-cran40/' && \
apt-get update -y && \
apt-get remove r-base-core -y && \
apt --fix-broken install -y && \
apt-get update -y && \
apt-get upgrade -y && \
apt-get install r-base-dev -y && \
R --no-save -e 'update.packages(checkBuilt = TRUE, ask = FALSE)'