Fix garbage collection trigger in standalone app with PySide2

Fixes `TypeError: <lambda>() missing 1 required positional argument: 'qobject'`.

ephyviewer/standalone.py

@@ -85,7 +85,7 @@ def load_dataset(self, neo_rawio_class=None, file_or_dir_names=[], io_params={})
         # delete window on close so that memory and file resources are released
         win.setAttribute(QT.WA_DeleteOnClose, True)
         win.destroyed.connect(
-            lambda qobject, i=len(self.windows)-1: self.free_resources(i))  # TODO: fix PySide2 TypeError
+            lambda *args, i=len(self.windows)-1: self.free_resources(i))
 
         win.show()