Replace 404 link with archive

src/tablib/formats/_xlsx.py

@@ -40,9 +40,10 @@ def export_set(cls, dataset, freeze_panes=True, invalid_char_subst="-", escape=F
 
         If ``freeze_panes`` is True, Export will freeze panes only after first line.
 
-        If ``dataset.title`` contains characters which are considered invalid for an XLSX file
-        sheet name (http://www.excelcodex.com/2012/06/worksheets-naming-conventions/), they will
-        be replaced with ``invalid_char_subst``.
+        If ``dataset.title`` contains characters which are
+        considered invalid for an XLSX file sheet name
+        (https://web.archive.org/web/20230323081941/https://www.excelcodex.com/2012/06/worksheets-naming-conventions/),
+        they will be replaced with ``invalid_char_subst``.
 
         If ``escape`` is True, formulae will have the leading '=' character removed.
         This is a security measure to prevent formulae from executing by default