picard: 2.6.3 -> 2.6.4

pkgs/applications/audio/picard/default.nix

···
 in
 pythonPackages.buildPythonApplication rec {
   pname = "picard";
-  version = "2.6.3";
+  version = "2.6.4";
 
   src = fetchFromGitHub {
     owner = "metabrainz";
     repo = pname;
     rev = "release-${version}";
-    sha256 = "sha256-bSqGgRXqHGjT+OYCEafsT/btVe+n91+L0kB8fnrywss=";
+    sha256 = "0lm7s9jy7z4an3xxj3gnxxf2xx045i157qaxysbdhcq5lwlmznc7";
   };
 
   nativeBuildInputs = [ gettext qt5.wrapQtAppsHook qt5.qtbase ]