BUG #18352: signature could not be verified for pgdg-common

The following bug has been logged on the website:

Bug reference:      18352
Logged by:          Michael Johnson
Email address:      michael@letsengage.com.au
PostgreSQL version: 12.17
Operating system:   RHEL 8.8
Description:

Error setting up repositories: failure: repodata/repomd.xml from
pgdg-common: [Errno 256] No more mirrors to try.
https://download.postgresql.org/pub/repos/yum/common/redhat/rhel-7Server-x86_64/repodata/repomd.xml:
[Errno -1] repomd.xml signature could not be verified for pgdg-common

After receiving this error, I made sure the GPG Key was up to date and it
still occurs. It was working when we checked last month.