当我们使用 wget命令下载不安全的https 域名下的内容时会提示如下内容：
cannot verify pkg.jenkins.io's certificate, issued by ‘/C=US/O=Let's Encrypt/CN=R3’
Issued certificate has expired. To connect to pkg.jenkins.io insecurely, use `--no-check-certificate'.
修复方法
sudo yum install -y ca-certificates
参考资料：