Update Dockerfile

Dockerfile

@@ -8,9 +8,7 @@ USER user
 ENV PATH="/home/user/.local/bin:$PATH"
 
 
-RUN set -x && \
-  apt-get update && \
-  apt-get install --no-install-recommends -y git \
+RUN apt-get install --no-install-recommends -y git \
   echo "Asia/Shanghai" >/etc/timezone && \
   git config --global user.email "filecodebox@@users.noreply.github.com" && \
   git config --global user.name "filecodebox" && \