Upgrade image to ubuntu 20.04

Author: nbren12

Makefile

@@ -13,7 +13,7 @@ OTHER_MOUNTS ?=
 
 # base images w/ or w/o CUDA
 ifeq ($(CUDA),n)
-	BASE_IMAGE ?=ubuntu:18.04
+	BASE_IMAGE ?=ubuntu:20.04
 	DEP_TAG_NAME ?=gnu7-mpich314-nocuda
 else
 	BASE_IMAGE ?=nvidia/cuda:10.2-devel-ubuntu18.04

docker/Dockerfile

@@ -25,7 +25,9 @@ FROM $MPI_IMAGE AS mpi_image
 
 FROM $BASE_IMAGE AS fv3gfs-environment
 
-RUN apt-get update && apt-get install -y \
+RUN apt-get update &&
+    DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends tzdata && \
+    apt-get install -y \
     wget \
     gcc \
     libtool-bin \