Don't copy the whole source tree into the final image, it already has…

… the built prez module and all dependencies installed in the venv, it just needs main.py and supporting files.

Dockerfile

@@ -50,6 +50,7 @@ RUN apk update && \
  bash
 
 WORKDIR /app
-COPY . .
+# prez module is already built as a package and installed in $VIRTUAL_ENV as a library
+COPY main.py pyproject.toml ./
 
 ENTRYPOINT uvicorn prez.app:app --host=${HOST:-0.0.0.0} --port=${PORT:-8000} --proxy-headers