[Dev] Add openEuler support in rpm-software-management/mock upstream

rpm-software-management/mock is a 'simple' chroot build environment manager for building RPMs. Link: https://github.com/rpm-software-management/mock

openEuler hasn't supported it yet, this feedback was coming from the OpenHPC community initially, this will help to OpenHPC support on openEuler work.

I also draft a PR on upstream repo:

https://github.com/rpm-software-management/mock/pull/964

Please help to review and leave comments directly if you have any questions.

Regards, Yikun