misc: add pyupgrade files/notes (#55867)

.git-blame-ignore-revs

@@ -11,3 +11,5 @@ e07c450d7c8a5f80aafe185c85ebed73fe39d9e7
 30bbc8c90f35f0cc49bfdb4244ff856d6766032d
 # misc: apply isort (#52856)
 34224c56aa3b855a6cfcf96af8f315c620eaa430
+# misc: apply pyupgrade (#55867)
+1ec4ad937602a52db6913e8ee9103fdb59be59f7

.pre-commit-config.yaml

@@ -11,3 +11,8 @@ 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']

README

@@ -40,8 +40,13 @@ isort is used to format the imports, using those parameters:
 
     isort --profile black --line-length 110
 
-There is .pre-commit-config.yaml to use pre-commit to automatically run black and isort
-before commits. (execute `pre-commit install` to install the git hook.)
+pyupgrade is used to automatically upgrade syntax, using those parameters:
+
+    pyupgrade --keep-percent-format --py37-plus
+
+There is .pre-commit-config.yaml to use pre-commit to automatically run black,
+isort and pyupgrade before commits. (execute `pre-commit install` to install
+the git hook.)
 
 
 Tests