Docker script update for Ubuntu 20.04

docker/centos/latest/dev/Dockerfile

@@ -0,0 +1,22 @@
+ARG dist=centos
+ARG tag=latest
+ARG username=acetcom
+FROM ${username}/${dist}-${tag}-open5gs-base
+
+MAINTAINER Sukchan Lee <acetcom@gmail.com>
+
+RUN yum -y install \
+        cscope \
+        vim \
+        sudo \
+        iputils \
+        net-tools
+
+COPY setup.sh /root
+
+ARG username=acetcom
+RUN useradd -m --uid=1000 ${username} && \
+    echo "${username} ALL=(root) NOPASSWD:ALL" > /etc/sudoers.d/${username} && \
+    chmod 0440 /etc/sudoers.d/${username}
+
+WORKDIR /home/${username}