Dockerfile: fix the image build

poetry.lock was removed from version control [1], but the Dockerfile
was not updated.

Also change the base image to python:3.9-bullseye
Debian buster has been discontinued [2], so bump to bullseye.
And python 3.9 is the minimal requried version at this time.

[1] ff326f3
[2] https://www.debian.org/releases/buster/

Signed-off-by: Ihor Solodrai <[email protected]>

Author: theihor

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.10-buster as builder
+FROM python:3.9-bullseye as builder
 
 RUN pip install poetry
 
@@ -9,13 +9,13 @@ ENV POETRY_NO_INTERACTION=1 \
 
 WORKDIR /app
 
-COPY pyproject.toml poetry.lock ./
+COPY pyproject.toml /app/pyproject.toml
 RUN touch README.md
 
 RUN poetry install --without dev --no-root && rm -rf $POETRY_CACHE_DIR
 
 # The runtime image, used to just run the code provided its virtual environment
-FROM python:3.10-slim-buster as runtime
+FROM python:3.9-bullseye as runtime
 LABEL maintainer="Ihor Solodrai <[email protected]>"
 
 RUN apt update && \