Pass bytes to QApplication()

Author: t20100

lib/matplotlib/backends/backend_qt5.py

@@ -121,7 +121,7 @@ def _create_qApp():
                 if display is None or not re.search(r':\d', display):
                     raise RuntimeError('Invalid DISPLAY variable')
 
-            qApp = QtWidgets.QApplication(["matplotlib"])
+            qApp = QtWidgets.QApplication([b"matplotlib"])
             qApp.lastWindowClosed.connect(qApp.quit)
         else:
             qApp = app