This commit fixes the deprecation error for resize_event (#157).

`resize_event` has been deprecated since matplotlib 3.6. This commmit
transitions from `resize_event` to `ResizeEvent` as recommended.

Ref: https://qiskit.org/ecosystem/metal/_modules/matplotlib/backend_bases.html

pyraf/MplCanvasAdapter.py

@@ -1,6 +1,7 @@
 import matplotlib
 matplotlib.use('TkAgg')  # set backend
 import matplotlib.backends.backend_tkagg as tkagg
+from matplotlib.backend_bases import ResizeEvent
 from .Ptkplot import hideTkCursor
 from .Ptkplot import FullWindowCursor
 import tkinter
@@ -90,7 +91,7 @@ def resize_widget(self, event):
         self._tkcanvas.create_image(int(width / 2),
                                     int(height / 2),
                                     image=self._tkphoto)
-        self.resize_event()
+        self.callbacks.process('resize_event', ResizeEvent('resize_event', self))
 
     def flush(self):