but the PROJ package on the same repository is proj-4.8.0-4.el7.x86_64.rpm with libproj.so.0.7.0 (the same thing with proj in the EPEL repository).
The package you have updated is therefore not updateable.
This would be a better question for the yum repo mailing list. If you haven't already, please try sending this issue there or see if it has already been reported.