Treewide: update some problematic homepages

These URLs are reported as problematic by Repology.
It could be a permanent redirection
or the page does not exist anymore

pkgs/development/python-modules/bugz/default.nix

@@ -17,7 +17,7 @@ buildPythonPackage {
   doCheck = false;
 
   meta = with stdenv.lib; {
-    homepage = http://www.liquidx.net/pybugz/;
+    homepage = "https://github.com/williamh/pybugz";
     description = "Command line interface for Bugzilla";
     license = licenses.gpl2;
     maintainers = [ maintainers.costrouc ];