Adding --no-check-certificate to yum repositories
Solution 1:
For one repo you can add the following in the repo configuration:
sslverify=0
For all repos, you can add the following to "/etc/yum.conf":
sslverify=false
Solution 2:
On CentOS 7.5, running this worked:
yum-config-manager --save --setopt=<REPONAME>.sslverify=false