BUG #16196: RPM package for PG 10.11 assumes that all Centos >= 7 use python2-libs, but 7.4 doesn't

The following bug has been logged on the website:

Bug reference: 16196
Logged by: Edmund Horner
Email address: ejrh00(at)gmail(dot)com
PostgreSQL version: 10.11
Operating system: Centos 7.4
Description:

Hi, we've had some trouble installing postgresql10-plpython on Centos 7.4,
which used to work, until 10.11 came out. The difference is that 10.11
depends on python2-libs rather than python-libs. I'm not hugely familiar
with the RHEL versions and packages but it kind of looks like python2-libs
doesn't appear until Centos 8.

https://pkgs.org/download/python2-libs

There's a comment in the spec saying "Support Python3 on RHEL 7.7+ natively"
but the conditional that determines whether to use python-libs or
python3-libs just checks for "0%{?rhel} <= 6".

Is it possible to check the minor part of the release version, too, and is
that appropriate?

Thanks for your work maintaining the RPMs. They've worked perfectly (except
for this little thing).

Cheers,
Edmund Horner