misc: add django-upgrade files/notes (#69798)

.pre-commit-config.yaml

@@ -1,6 +1,16 @@
 # See https://pre-commit.com for more information
 # See https://pre-commit.com/hooks.html for more hooks
 repos:
+-   repo: https://github.com/asottile/pyupgrade
+    rev: v2.20.0
+    hooks:
+    - id: pyupgrade
+      args: ['--keep-percent-format', '--py37-plus']
+-   repo: https://github.com/adamchainz/django-upgrade
+    rev: 1.10.0
+    hooks:
+    - id: django-upgrade
+      args: ['--target-version', '2.2']
 -   repo: https://github.com/psf/black
     rev: 22.3.0
     hooks:
@@ -11,11 +21,6 @@ repos:
     hooks:
     - id: isort
       args: ['--profile', 'black', '--line-length', '110']
--   repo: https://github.com/asottile/pyupgrade
-    rev: v2.20.0
-    hooks:
-    - id: pyupgrade
-      args: ['--keep-percent-format', '--py37-plus']
 - repo: https://github.com/rtts/djhtml
   rev: 'v1.5.2'
   hooks:

README

@@ -347,9 +347,12 @@ djhtml is used to automatically indent html files, using those parameters:
 
     djhtml --tabwidth 2
 
-There is .pre-commit-config.yaml to use pre-commit to automatically run black,
-isort, pyupgrade, and djhtml before commits. (execute `pre-commit install`
-to install the git hook.)
+django-upgrade is used to automatically upgrade Django syntax, using those parameters:
+
+    django-upgrade --target-version 2.2
+
+There is .pre-commit-config.yaml to use pre-commit to automatically run these tools
+before commits. (execute `pre-commit install` to install the git hook.)
 
 Remarks
 =======