E: Package 'gnupg' has no installation candidate
这个该怎么解决呢?
gnupg, gnupg2 and gnupg1 do not seem to be installed, but one of them is required for this operation在 Docker 中 Ubuntu 添加密钥时遇到的错误 Step 4/14 : RUN apt-key adv --keyserver keyserver.ubuntu.c...