use debian packages

Dockerfile

 
-FROM debian:bullseye 
+FROM debian:bookworm
     
 # Python Packages 
-RUN apt-get update && apt-get install -y \
+RUN set -x && \
+    apt update && \
+    apt install -y --no-install-recommends \
     python3 \
-    python3-pip 
+    python3-pip \
+    python3-flask \
+    python3-gunicorn \
+    python3-jinja2 \
+    apt -qq clean
 
-# pip Packages
-RUN pip3 install \     
-    flask==1.0.2 \     
-    gunicorn \
-    --upgrade 
     
 # start Script 
 COPY entrypoint_dev.sh /opt/entrypoint_dev.sh