CentOS更换AppStream源

解决方案
第1步：复制指令。

bash <(curl -sSL https://linuxmirrors.cn/main.sh)

第2步：然后输入数字11-1等待跑完即可。

[root@localhost ~]# bash <(curl -sSL https://linuxmirrors.cn/main.sh)
curl: (60) Peer's Certificate issuer is not recognized.
More details here: http://curl.haxx.se/docs/sslcerts.html

curl performs SSL certificate verification by default, using a "bundle"
 of Certificate Authority (CA) public keys (CA certs). If the default
 bundle file isn't adequate, you can specify an alternate file
 using the --cacert option.
If this HTTPS server uses a certificate signed by a CA represented in
 the bundle, the certificate verification probably failed due to a
 problem with the certificate (it might be expired, or the name might
 not match the domain name in the URL).
If you'd like to turn off curl's verification of the certificate, use
 the -k (or --insecure) option.

报错是由于证书错误引起的，更新下证书

yum install -y ca-certificates
update-ca-trust force-enable
update-ca-trust extract