Same here, but it seems to be a problem on the repository side. Should be fixed soon, however, according to this:
https://www.centos.org/forums/viewtopic.php?t=63018
Postby avij » 2017/06/21 17:44:44
This is an EPEL problem, and EPEL is not managed by CentOS.
That said, there has indeed been a problem in EPEL today and fixed EPEL repository files are currently being synced to mirrors. It may take a while. yum clean all may help, and yum update may also work.