use ubuntu instead of jhub base image

venv/Dockerfile

-FROM jupyter/base-notebook:hub-2.1.1
-USER root
+FROM ubuntu:focal-20220316
+
 ENV DEBIAN_FRONTEND noninteractive
-RUN apt update && apt remove -y curl libcurl4 librtmp1 && apt autoremove -y && apt install -y curl
+
+ENV USERNAME=jovyan
+
+# create the app user
+RUN adduser --uid 1000 --ingroup users --gecos "" --disabled-password ${USERNAME}
+
+RUN apt update && \
+    apt -y upgrade && \
+    apt clean && \
+    rm -rf /var/lib/apt/lists/*
+
+COPY requirements_apt.txt /tmp/requirements_apt.txt
+COPY requirements_pip.txt /tmp/requirements_pip.txt
+
+RUN apt update && \
+    cat /tmp/requirements_apt.txt | xargs apt install -yq && \
+    apt clean && \
+    rm -rf /var/lib/apt/lists/* && \
+    pip install -r /tmp/requirements_pip.txt && \
+    chown -R ${USERNAME}:users ${HOME} && \
+    rm /tmp/requirements_pip.txt && \
+    rm /tmp/requirements_apt.txt
+
+USER jovyan

venv/requirements_apt.txt

+bash
+ca-certificates
+curl
+python3
+python3-pip
+libc6
+libstdc++6
+rsync
+tar
+uuid-runtime
+vim
+wget

venv/requirements_pip.txt

+jupyterhub==2.1.1
+
+jupyterlab