Update Python Folder.icns icon file to match new macOS look (GH-1780)

Patch by Thomas Jones.
diff --git a/Mac/Icons/Python Folder.icns b/Mac/Icons/Python Folder.icns
index ae766ee..3658f5e 100644
--- a/Mac/Icons/Python Folder.icns
+++ b/Mac/Icons/Python Folder.icns
Binary files differ