compile libsass dependency in builder step

release.dockerfile

@@ -1,8 +1,24 @@
-FROM python:3.11.3-slim
+FROM python:3.11.3-slim as builder
+
+RUN apt-get update && \
+    DEBIAN_FRONTEND=noninteractive TZ=Etc/UTC \
+    apt-get install -y --no-install-recommends \
+    build-essential \
+    && rm -rf /var/lib/apt/lists/* \
+    && apt-get clean
+
+RUN python -m pip install --upgrade pip
+
+RUN python -m pip install --upgrade libsass
+
+FROM python:3.11.3-slim as release
+COPY --from=builder /usr/local/lib/python3.11/site-packages /usr/local/lib/python3.11/site-packages
 ARG VERSION
 
 LABEL maintainer="Zauberzeug GmbH <info@zauberzeug.com>"
 
+RUN python -m pip install --upgrade pip
+
 RUN python -m pip install nicegui==$VERSION itsdangerous isort docutils requests
 
 WORKDIR /app