在Docker构建期间第二次apt-get更新后，Ubuntu21.04中的GPG错误

构建以下 Docker 文件时出错

FROM ubuntu:21.04

RUN apt-get update && 
    apt-get install --no-install-recommends -y curl=7.* && 
    apt-get install --no-install-recommends -y unzip=6.* && 
    rm -rf /var/lib/apt/lists/*

RUN apt-get update && 
    mkdir -p /usr/share/man/man1 && 
    apt-get install --no-install-recommends -y maven=3.6.3-5 && 
    apt-get clean && 
    rm -rf /var/lib/apt/lists/*

第二次apt-get update运行时出现错误。

错误如下：-

E: The repository 'http://security.ubuntu.com/ubuntu hirsute-security InRelease' is not signed.
W: GPG error: http://archive.ubuntu.com/ubuntu hirsute InRelease: gpgv, gpgv2 or gpgv1 required for verification, but neither seems installed
E: The repository 'http://archive.ubuntu.com/ubuntu hirsute InRelease' is not signed.
W: GPG error: http://archive.ubuntu.com/ubuntu hirsute-updates InRelease: gpgv, gpgv2 or gpgv1 required for verification, but neither seems installed
E: The repository 'http://archive.ubuntu.com/ubuntu hirsute-updates InRelease' is not signed.
W: GPG error: http://archive.ubuntu.com/ubuntu hirsute-backports InRelease: gpgv, gpgv2 or gpgv1 required for verification, but neither seems installed
E: The repository 'http://archive.ubuntu.com/ubuntu hirsute-backports InRelease' is not signed.

任何形式的帮助将不胜感激。

回答