misc: change pyupgrade target version to 3.9 (#75442)

.pre-commit-config.yaml

@@ -2,10 +2,10 @@
 # See https://pre-commit.com/hooks.html for more hooks
 repos:
 -   repo: https://github.com/asottile/pyupgrade
-    rev: v3.1.0
+    rev: v3.3.1
     hooks:
     - id: pyupgrade
-      args: ['--keep-percent-format', '--py37-plus']
+      args: ['--keep-percent-format', '--py39-plus']
 -   repo: https://github.com/adamchainz/django-upgrade
     rev: 1.13.0
     hooks:

src/authentic2/utils/evaluate.py

@@ -17,7 +17,6 @@
 import ast
 import logging
 import re
-import sys
 
 import dns.exception
 import dns.resolver
@@ -203,10 +202,7 @@ class BaseExpressionValidator(ast.NodeVisitor):
 
 
 # python 3.8 introduced ast.Constant to replace Num, Str, Bytes and NameConstant (True, False, None)
-if sys.version_info < (3, 8):
-    CONSTANT_CLASSES = (ast.Num, ast.Str, ast.Bytes)
-else:
-    CONSTANT_CLASSES = (ast.Constant,)
+CONSTANT_CLASSES = (ast.Constant,)
 
 
 class ConditionValidator(BaseExpressionValidator):
@@ -272,16 +268,7 @@ class ConditionValidator(BaseExpressionValidator):
     def check_Subscript(self, node):
         # check subscript are constant number or strings
         ok = True
-        if sys.version_info >= (3, 9):
-            ok = isinstance(node.slice, CONSTANT_CLASSES)
-        elif sys.version_info >= (3, 8):
-            ok = (
-                isinstance(node.slice, ast.Index)
-                and isinstance(node.slice.value, CONSTANT_CLASSES)
-                and isinstance(node.slice.value.value, (int, str, bytes))
-            )
-        else:
-            ok = isinstance(node.slice, ast.Index) and isinstance(node.slice.value, CONSTANT_CLASSES)
+        ok = isinstance(node.slice, CONSTANT_CLASSES)
         if not ok:
             raise ExpressionError(
                 _('subscript index MUST be a constant'), code='invalid-subscript', node=node