Dockerfile: use recent Python

Dockerfile

@@ -1,28 +1,18 @@
 #
 # To build:
-# > sudo docker build -t scrapyrt .
+# > docker build -t scrapyrt .
 #
 # to start as daemon with port 9080 of api exposed as 9080 on host
 # and host's directory ${PROJECT_DIR} mounted as /scrapyrt/project
 #
-# > sudo docker run -p 9080:9080 -tid -v ${PROJECT_DIR}:/scrapyrt/project scrapyrt
+# > docker run -p 9080:9080 -tid -v ${PROJECT_DIR}:/scrapyrt/project scrapyrt
 #
 
-FROM ubuntu:18.04
-
-ENV DEBIAN_FRONTEND noninteractive
-
-RUN apt-get update && \
-    apt-get install -y python3 python3-dev  \
-    libffi-dev libxml2-dev libxslt1-dev zlib1g-dev libssl-dev wget
+FROM python:3.10-slim-buster
 
 RUN mkdir -p /scrapyrt/src /scrapyrt/project
 RUN mkdir -p /var/log/scrapyrt
 
-RUN wget -O /tmp/get-pip.py "https://bootstrap.pypa.io/get-pip.py" && \
-    python3 /tmp/get-pip.py "pip==19.3.1" && \
-    rm /tmp/get-pip.py
-
 ADD . /scrapyrt/src
 RUN pip install /scrapyrt/src