fix for flask

Dockerfile

@@ -2,8 +2,7 @@ FROM python:3.9
 
 WORKDIR /code
 COPY ./requirements.txt /code/requirements.txt
-COPY ./app.py /code/app.py
+RUN pip install --no-cache-dir --upgrade -r /code/requirements.txt
 
-RUN pip install -r requirements.txt
 COPY . .
 CMD ["python", "app.py"]