update Dockerfile

Author: blmdxiao

Diff for: Dockerfile

@@ -8,7 +8,7 @@ WORKDIR /app
 COPY . /app
 
 # Install any needed packages specified in requirements.txt
-RUN pip install --no-cache-dir -r requirements.txt
+RUN pip install -r requirements.txt
 
 # Grant execution permissions to the start-up script
 RUN chmod a+x start.sh