fix: User Literal from typing_extensions as its not supported in typing in py 3.7

- https://mypy.readthedocs.io/en/stable/literal_types.html

erpnext/manufacturing/doctype/bom_update_log/bom_update_log.py

@@ -1,11 +1,12 @@
 # Copyright (c) 2022, Frappe Technologies Pvt. Ltd. and contributors
 # For license information, please see license.txt
-from typing import Dict, List, Literal, Optional
+from typing import Dict, List, Optional
 
 import frappe
 from frappe import _
 from frappe.model.document import Document
 from frappe.utils import cstr, flt
+from typing_extensions import Literal
 
 from erpnext.manufacturing.doctype.bom_update_tool.bom_update_tool import update_cost
 

erpnext/manufacturing/doctype/bom_update_tool/bom_update_tool.py

@@ -2,7 +2,9 @@
 # For license information, please see license.txt
 
 import json
-from typing import TYPE_CHECKING, Dict, Literal, Optional, Union
+from typing import TYPE_CHECKING, Dict, Optional, Union
+
+from typing_extensions import Literal
 
 if TYPE_CHECKING:
 	from erpnext.manufacturing.doctype.bom_update_log.bom_update_log import BOMUpdateLog