syncplay: upgrade from Qt4 to Qt5 dependency

Syncplay automatically detects whether it has access to PySide, which
binds Qt4, or PySide2, which binds Qt5. By simply updating the
dependencies, we can upgrade Syncplay to Qt5.

pkgs/applications/networking/syncplay/default.nix

@@ -1,4 +1,4 @@
-{ lib, fetchFromGitHub, buildPythonApplication, pyside, twisted, certifi }:
+{ lib, fetchFromGitHub, buildPythonApplication, pyside2, shiboken2, twisted, certifi }:
 
 buildPythonApplication rec {
   pname = "syncplay";
@@ -13,7 +13,7 @@ buildPythonApplication rec {
     sha256 = "0afh2a0l1c3hwgj5q6wy0v5iimg8qcjam3pw7b8mf63lasx6iqk4";
   };
 
-  propagatedBuildInputs = [ pyside twisted certifi ] ++ twisted.extras.tls;
+  propagatedBuildInputs = [ pyside2 shiboken2 twisted certifi ] ++ twisted.extras.tls;
 
   makeFlags = [ "DESTDIR=" "PREFIX=$(out)" ];