fix:基础镜像修改

Author: Wenruli

src/backend/base.Dockerfile

@@ -15,7 +15,7 @@ RUN apt-get update && \
     && rm -rf /var/lib/apt/lists/*
 
 # 安装 FFmpeg
-RUN apt-get install -y --no-install-recommends ffmpeg && rm -rf /var/lib/apt/lists/*
+RUN apt-get update && apt-get install -y --no-install-recommends ffmpeg && rm -rf /var/lib/apt/lists/*
 
 
 # 安装 pandoc