Install the Latest PostgreSQL Yum Repository for CentOS

Keeping PostgreSQL updated via yum should be done via the pgdg yum repository supplied by

The latest CentOS PostgreSQL repo can be viewed here.  

You will need to download the repo and then install using rpm as shown below.

rpm -Uhv pgdg-centos-8.4-1.noarch.rpm

Another helpful postgresql install and management link is located here.