We need to update Centos 7 containers due to EOL

[vkarak]

mirrorlist.centos.org is no more available so containers such as the tmod32 fail to build. Proposed solution can be found here:

https://serverfault.com/questions/1161816/mirrorlist-centos-org-no-longer-resolve#:~:text=Centos%207%20has%20reached%20EOL,centos.org%20will%20work%20well.