Update Dockerfile (#435)

Dockerfile

@@ -1,12 +1,11 @@
-# syntax=docker/dockerfile:1
-FROM python:3.12-alpine3.17
-
+FROM python:3.13-slim-trixie AS builder
 WORKDIR /app
-
+COPY pyproject.toml poetry.lock* ./
+RUN pip install --no-cache-dir poetry==2.2.1 poetry-plugin-export && \
+    poetry export -f requirements.txt --without-hashes --output requirements.txt
+RUN python -m venv /venv && \
+    /venv/bin/pip install --no-cache-dir -r requirements.txt
 COPY . .
-
-RUN pip install --no-cache-dir poetry==1.3.2 && \
-  poetry export -f requirements.txt > /tmp/requirements.txt && \
-  pip install -r /tmp/requirements.txt
-
-ENTRYPOINT ["python", "/app/rfd_notify/cli.py", "-c", "config.yml"]
+ENV PATH="/venv/bin:$PATH"
+RUN apt-get purge -y --allow-remove-essential bash
+ENTRYPOINT ["/venv/bin/python", "rfd_notify/cli.py", "-c", "config.yml"]