Update Dockerfile

Dockerfile

@@ -24,7 +24,6 @@ FROM alpine
 WORKDIR /work
 
 # 设置时区
-RUN sed -i 's/dl-cdn.alpinelinux.org/mirrors.ustc.edu.cn/g' /etc/apk/repositories
 RUN apk add --no-cache tzdata \
     && ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime \
     && echo "Asia/Shanghai" > /etc/timezone \