Bump v4.7.3

Bump v4.7.3

Update EPEL reference for pgo-deployer container

This required an updated URL.

Fix doc build error

There was still a reference to Postgres 9.5 in one of the
variables, which we no longer support.

version bump to 4.5.4 (CrunchyData#2668)

* version bump to 4.5.4

* fixed typo

bump pg versions and pgo version

Updates to v4.6.4 release notes

Update Postgres version reference for 4.7.2 release

Ensure the references are for Postgres 13.4.

Image Updates

Image updates for PGO scripts, installers, examples and documentation.

Issue: [ch12324]

Image Updates

Image updates for PGO scripts, installers, examples and documentation.

Issue: [ch12324]