catt: Use hash and SRI hashes

With the python package set moving to hash, overriding the fetcher and
reintroducing sha256 breaks eval, due to multiple hashes passed.

Also set an explicit format in buildPythonApplication.

pkgs/applications/video/catt/default.nix

@@ -21,7 +21,7 @@ let
         version = "7.1.2";
         src = oldAttrs.src.override {
           inherit version;
-          sha256 = "06kbzd6sjfkqan3miwj9wqyddfxc2b6hi7p5s4dvqjb3gif2bdfj";
+          hash = "sha256-0rUlXHxjSbwb0eWeCM0SrLvWPOZJ8liHVXg6qU37axo=";
         };
       });
 
@@ -40,6 +40,7 @@ with py.pkgs;
 buildPythonApplication rec {
   pname = "catt";
   version = "0.12.7";
+  format = "setuptools";
 
   src = fetchPypi {
     inherit pname version;