Add explicit conflicts

file /usr/bin/lesscpy from install of python3-lesscpy-0.13.0-3.fc28.noarch
conflicts with file from package python2-lesscpy-0.10.1-13.fc28.noarch

python-lesscpy.spec

@@ -9,7 +9,7 @@
 
 Name:           python-%{pypi_name}
 Version:        0.13.0
-Release:        3%{?dist}
+Release:        4%{?dist}
 Summary:        Lesscss compiler
 
 License:        MIT
@@ -58,6 +58,9 @@ BuildRequires: python3-coverage
 BuildRequires: python3-six
 %{?python_provide:%python_provide python3-lesscpy}
 
+# executable moved to py3 package
+Conflicts:   python2-lesscpy < 0.13.0-2
+
 %description -n python3-lesscpy
 A compiler written in python 3 for the lesscss language.  For those of us not
 willing/able to have node.js installed in our environment.  Not all features
@@ -108,6 +111,9 @@ ln -s ./lesscpy %{buildroot}/%{_bindir}/py3-lesscpy
 
 
 %changelog
+* Wed Jun 13 2018 Miro Hrončok <mhroncok@redhat.com> - 0.13.0-4
+- Add explicit conflicts
+
 * Tue Jun 12 2018 Miro Hrončok <mhroncok@redhat.com> - 0.13.0-3
 - General spec cleanup
 - Add missing dependency on six