Use macros for Shellfu and Saturnin requirements

packaging/template.spec

+%define shellfu_req shellfu >= 0.10.4, shellfu < 0.11
+%define saturnin_req shellfu-bash-saturnin >= 0.4.10, shellfu-bash-saturnin < 0.5
+
 Name:           __MKIT_PROJ_PKGNAME__
 Version:        __MKIT_PROJ_VERSION__
 Release:        1%{?dist}
 License:        LGPLv2
 Source0:        %{name}-%{version}.tar.gz
 BuildArch:      noarch
-BuildRequires:  shellfu >= 0.10, shellfu < 0.11
-BuildRequires:  shellfu-bash-saturnin >= 0.4.8, shellfu-bash-saturnin < 0.5.0
+BuildRequires:  %saturnin_req
+BuildRequires:  %shellfu_req
 
-Requires:       shellfu >= 0.10, shellfu < 0.11
-Requires:       shellfu-bash-saturnin >= 0.4.8, shellfu-bash-saturnin < 0.5.0
+Requires:   %shellfu_req
+Requires:   %saturnin_req
 %description
 saturnin is Shellfu library that helps you easily build toolkit from
 various scripts that you may have lying around.  Instead of having a