reverting datascience-notebook back to R 3.6.3

datascience-notebook/Dockerfile

@@ -50,8 +50,8 @@ USER $NB_UID
 
 # R packages including IRKernel which gets installed globally.
 RUN conda install --quiet --yes \
-    'r-base=4.0.0' \
-    'r-caret=6.*' \
+    'r-base=3.6.3' \
+    'r-caret=6.0*' \
     'r-crayon=1.3*' \
     'r-devtools=2.3*' \
     'r-forecast=8.12*' \
@@ -60,22 +60,20 @@ RUN conda install --quiet --yes \
     'r-htmlwidgets=1.5*' \
     'r-irkernel=1.1*' \
     'r-nycflights13=1.0*' \
+    'r-plyr=1.8*' \
     'r-randomforest=4.6*' \
     'r-rcurl=1.98*' \
-    'r-reticulate=1.16*' \
-    'r-rmarkdown=2.2*' \
+    'r-reshape2=1.4*' \
+    'r-rmarkdown=2.1*' \
     'r-rsqlite=2.2*' \
     'r-shiny=1.4*' \
     'r-tidyverse=1.3*' \
-    'r-tidymodels=0.1*' \
+    'rpy2=3.1*' \
     && \
     conda clean --all -f -y && \
     fix-permissions "${CONDA_DIR}" && \
     fix-permissions "/home/${NB_USER}"
 
-# Install e1071 R package (dependency of the caret R package)
-RUN conda install --quiet --yes r-e1071
-
 # Add Julia packages. Only add HDF5 if this is not a test-only build since
 # it takes roughly half the entire build time of all of the images on Travis
 # to add this one package and often causes Travis to timeout.
@@ -92,4 +90,4 @@ RUN julia -e 'import Pkg; Pkg.update()' && \
     rm -rf "${HOME}/.local" && \
     fix-permissions "${JULIA_PKGDIR}" "${CONDA_DIR}/share/jupyter"
 
-WORKDIR $HOME
+WORKDIR $HOME
\ No newline at end of file