001、问题：
R 语言安装“devtools”
ERROR: dependencies ‘openssl’, ‘curl’ are not available for package ‘credentials’
002、解决方法：
- dependencies credentials available openssl packagedependencies credentials available openssl service_base information dependency available dependencies transitive for available dependency available warning locfit available referred package another available docker-ce centos7 package dependent multiple packages versions devdependency dependency package json dependent requiring packages versions available时报package kubelet