Version update for - 8.1.0 | Add SIMPLE Org plan

Author: sangeet-joy_xero

Diff for: docs/v1/payroll-uk/index.html

@@ -2562,7 +2562,7 @@
   "type" : "string",
   "description" : "The employee's NI Category letter.",
   "example" : "I",
-  "enum" : [ "A", "B", "C", "D", "E", "F", "H", "I", "J", "K", "L", "M", "N", "S", "V", "X", "Z" ]
+  "enum" : [ "A", "B", "C", "F", "H", "I", "J", "L", "M", "S", "V", "X", "Z", "D", "E", "K", "N" ]
 };
       defs["NICategory_oneOf"] = {
   "title" : "",

Diff for: xero_python/accounting/models/organisation.py

@@ -988,6 +988,7 @@ def _class(self, _class):
             "IGNITE",
             "GROW",
             "COMPREHENSIVE",
+            "SIMPLE",
             "None",
         ]  # noqa: E501