yum- y updateにおいて、
The GPG keys listed for the "rhel 7 x86_64 - mondorescue Vanilla Packages" repository are already installed but they are not correct for this package.
Check that the correct key URLs are configured for this repository.
と出た場合、
# cd
# wget ftp://ftp.mondorescue.org/rhel/7/x86_64/perl-ProjectBuilder-0.14.6-1.rhel7.noarch.rpm
# rpm --delsign perl-ProjectBuilder-0.14.6-1.rhel7.noarch.rpm
# yum localinstall -y --nogpgcheck perl-ProjectBuilder-0.14.6-1.rhel7.noarch.rpm
# yum -y update
# reboot
で解決する。
参照：http://fnya.cocolog-nifty.com/blog/2017/12/cent0s-7-perl-p.html
