Fix no attribute 'join_path' error in Windows test (#4995)

Author: abravalheri

newsfragments/4995.misc.rst

@@ -0,0 +1 @@
+Fixed ``no attribute 'join_path'`` error in Windows test

setuptools/tests/test_windows_wrappers.py

@@ -48,7 +48,7 @@ def create_script(cls, tmpdir):
 
         # also copy cli.exe to the sample directory
         with (tmpdir / cls.wrapper_name).open('wb') as f:
-            w = resources.files('setuptools').join_path(cls.wrapper_source).read_bytes()
+            w = resources.files('setuptools').joinpath(cls.wrapper_source).read_bytes()
             f.write(w)