Update to Poetry (resolves #27 and #29)

Dockerfile

@@ -1,13 +1,33 @@
-# syntax=docker/dockerfile:1.9
-FROM --platform=$BUILDPLATFORM python:3.12-alpine
+FROM python:3.12.2-alpine3.18 AS base
 
+FROM base AS builder
+
+ENV PYTHONFAULTHANDLER=1 \
+  PYTHONUNBUFFERED=1 \
+  PYTHONHASHSEED=random \
+  PIP_NO_CACHE_DIR=off \
+  PIP_DISABLE_PIP_VERSION_CHECK=on \
+  PIP_DEFAULT_TIMEOUT=100 \
+  POETRY_NO_INTERACTION=1 \
+  POETRY_VIRTUALENVS_CREATE=false \
+  PATH="$PATH:/runtime/bin" \
+  PYTHONPATH="$PYTHONPATH:/runtime/lib/python3.12/site-packages" \
+  # Versions:
+  POETRY_VERSION=1.7.1
+
+# System deps:
+RUN apk add build-base unzip wget python3-dev libffi-dev
+RUN pip install "poetry==$POETRY_VERSION"
+
+WORKDIR /src
+
+# Generate requirements and install *all* dependencies.
+COPY pyproject.toml poetry.lock /src/
+RUN poetry export --dev --without-hashes --no-interaction --no-ansi -f requirements.txt -o requirements.txt
+RUN pip install --prefix=/runtime --force-reinstall -r requirements.txt
+
+FROM base AS runtime
+COPY --from=builder /runtime /usr/local
+COPY . /app
 WORKDIR /app
-
-COPY requirements.txt /app
-RUN --mount=type=cache,target=/root/.cache/pip \
-    pip3 install -r requirements.txt
-
-COPY app.py /app
-
-ENTRYPOINT ["python3"]
-CMD ["app.py"]
+CMD ["/usr/local/bin/uvicorn", "simple_webfinger.app:app", "--host", "0.0.0.0", "--port", "80", "--proxy-headers"]