feat: Drop support for Python 2 and remove compatibility code

This removes support for Python 2, and drops most of the compatibility
code that was used to support both Python 2 and Python 3.

send2trash/mac/legacy.py

@@ -9,7 +9,6 @@ from __future__ import unicode_literals
 from ctypes import cdll, byref, Structure, c_char, c_char_p
 from ctypes.util import find_library
 
-from send2trash.compat import binary_type
 from send2trash.util import preprocess_paths
 
 Foundation = cdll.LoadLibrary(find_library("Foundation"))
@@ -42,7 +41,7 @@ def check_op_result(op_result):
 
 def send2trash(paths):
     paths = preprocess_paths(paths)
-    paths = [path.encode("utf-8") if not isinstance(path, binary_type) else path for path in paths]
+    paths = [path.encode("utf-8") if not isinstance(path, bytes) else path for path in paths]
     for path in paths:
         fp = FSRef()
         opts = kFSPathMakeRefDoNotFollowLeafSymlink