Button widget is not working as a child to ttk widgets.

[Saadmairaj]

Describe the bug
The button widget is throwing an error when placed inside of a ttk.frame or any ttk widget as a parent to the tkmacosx Button.

To Reproduce

import tkinter as tk
import tkinter.ttk as ttk
import tkmacosx as tkm

root = tk.Tk()
frame = ttk.Frame(root)
frame.pack()
button = tkm.Button(frame)
button.pack()
root.mainloop()

Expected behavior

Traceback (most recent call last):
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  File "/Users/saad/anaconda3/envs/base3.9/lib/python3.9/site-packages/tkmacosx/basewidgets/button_base.py", line 143, in borderless
    if self.cnf.get('bordercolor') == self.master['bg']:
  File "/Users/saad/anaconda3/envs/base3.9/lib/python3.9/tkinter/__init__.py", line 1644, in cget
    return self.tk.call(self._w, 'cget', '-' + key)
_tkinter.TclError: unknown option "-bg"

• Version: 1.0.0 or below