BUG #17224: Postgres Yum repo mirror has expired SSL certificate

The following bug has been logged on the website:

Bug reference:      17224
Logged by:          Matt Bush
Email address:      postgres@netlag.com
PostgreSQL version: 13.3
Operating system:   Linux (CentOS)
Description:

In our automation we first install the PGDG Yum repo
pgdg-redhat-repo-latest.noarch.rpm and then install the individual
components needed by our applications and servers.  Starting about a week
ago, with the expiration of the Let's Encrypt! CA cert, we've been
experiencing intermittent repo failures due to an expired SSL cert on one of
the repo mirrors.

$ curl -v
https://download.postgresql.org/pub/repos/yum/14/redhat/rhel-7-x86_64/repodata/repomd.xml
*   Trying 217.196.149.55...
* TCP_NODELAY set
* Connected to download.postgresql.org (217.196.149.55) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* Cipher selection:
ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/cert.pem
  CApath: none
* TLSv1.2 (OUT), TLS handshake, Client hello (1):
* TLSv1.2 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (OUT), TLS alert, Server hello (2):
* SSL certificate problem: certificate has expired
* stopped the pause stream!
* Closing connection 0
curl: (60) SSL certificate problem: certificate has expired
More details here: https://curl.haxx.se/docs/sslcerts.html