BUG #15770: PostgreSQL rpm package got to be impossible to be installed in Amazon Linux 2

The following bug has been logged on the website:

Bug reference: 15770
Logged by: Yu ONODA
Email address: yuonoda95(at)gmail(dot)com
PostgreSQL version: 11.2
Operating system: Amazon Linux release 2 (Karoo)
Description:

Hi there,

I'm installing PostgreSQL from RPM package here (
https://download.postgresql.org/pub/repos/yum/11/redhat/rhel-7-x86_64/pgdg-centos11-11-2.noarch.rpm
) to Amazon Linux 2. This package was successfully installed to the
environment a few days ago. But since the latest change at April 17th,
installing this package cause an error like this.

# yum install
https://download.postgresql.org/pub/repos/yum/11/redhat/rhel-7-x86_64/pgdg-centos11-11-2.noarch.rpm
Loaded plugins: extras_suggestions, langpacks, priorities, update-motd
pgdg-centos11-11-2.noarch.rpm
| 5.6 kB 00:00:00
Examining /var/tmp/yum-root-WK8QVa/pgdg-centos11-11-2.noarch.rpm:
pgdg-redhat-repo-42.0-4.noarch
Marking /var/tmp/yum-root-WK8QVa/pgdg-centos11-11-2.noarch.rpm to be
installed
Resolving Dependencies
--> Running transaction check
---> Package pgdg-redhat-repo.noarch 0:42.0-4 will be installed
--> Processing Dependency: /etc/redhat-release for package:
pgdg-redhat-repo-42.0-4.noarch
amzn2-core
| 2.4 kB 00:00:00
205 packages excluded due to repository priority protections
--> Processing Dependency: /etc/redhat-release for package:
pgdg-redhat-repo-42.0-4.noarch
--> Finished Dependency Resolution
Error: Package: pgdg-redhat-repo-42.0-4.noarch
(/pgdg-centos11-11-2.noarch)
Requires: /etc/redhat-release
You could try using --skip-broken to work around the problem
You could try running: rpm -Va --nofiles --nodigest

This should occur because I use Amazon Linux2. I'm still uncertain if this
is a bug or correct behaviour. I report this for your information.

Thanks,
Yu