CentOS 8: nothing provides python-PyYAML, nothing provides python-dateutil, nothing provides python-lxml, nothing provides python >= 2.6

[olegantonyan]

Cannot build for CentOS 8: nothing provides python-PyYAML, nothing provides python-dateutil, nothing provides python-lxml, nothing provides python >= 2.6

  Substitute: python python3
  Substitute: python-PyYAML python3-PyYAML
  Substitute: python-dateutil python3-dateutil
  Substitute: python-lxml python3-lxml

in project config doesn't help

[olegantonyan]

Made a small progress

%if 0%{?centos_version} >= 800
Macros:
%_with_python3 1
:Macros
%endif

this leads to a new error: nothing provides python3-base
Ignore doesn't work once again.

To fix this I had to edit spec file: https://build.opensuse.org/package/rdiff/home:oleg_antonyan/obs-service-tar_scm?opackage=obs-service-tar_scm&oproject=openSUSE%3ATools&rev=2
Basically this line https://github.com/openSUSE/obs-service-tar_scm/blob/master/dist/obs-service-tar_scm.spec#L151 should be removed for CentOS 8