Add project URL

slop.spec.in

 Version:    __SLOP_VERSION__
 Release:    __SLOP_RELEASE__%{?dist}
 Summary:    Select Operation
+URL:        https://github.com/naelstrof/slop
 
 License:    GPLv3
 Source0:    __SLOP_URLBASE__/archive/v%{version}.tar.gz