update dockerfile

Dockerfile

@@ -6,7 +6,7 @@ RUN  apt-get update && \
       rm -rf /var/lib/apt/lists/*
 ADD requirements.txt requirements.txt
 RUN pip install --upgrade pip  && \
-        pip install --no-cache-dir -r requirements.txt -i  https://mirrors.aliyun.com/pypi/simple  && \
+        pip install --no-cache-dir -r requirements.txt   && \
         pip install --no-cache-dir gunicorn[gevent] && \
         pip cache purge