[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/asottile/pyupgrade: v2.12.0 → v2.13.0](asottile/pyupgrade@v2.12.0...v2.13.0)
- [github.com/psf/black: 20.8b1 → 21.4b0](psf/black@20.8b1...21.4b0)
- https://gitlab.com/PyCQA/flake8 → https://github.com/PyCQA/flake8
- [github.com/PyCQA/flake8: 3.9.0 → 3.9.1](PyCQA/flake8@3.9.0...3.9.1)

.pre-commit-config.yaml

@@ -10,7 +10,7 @@ repos:
     -   id: debug-statements
     -   id: end-of-file-fixer
 -   repo: https://github.com/asottile/pyupgrade
-    rev: v2.12.0
+    rev: v2.13.0
     hooks:
     -   id: pyupgrade
         args: [--py36-plus]
@@ -25,16 +25,16 @@ repos:
       language: python
       types: [python]
 -   repo: https://github.com/psf/black
-    rev: 20.8b1
+    rev: 21.4b0
     hooks:
     -   id: black
 -   repo: https://github.com/asottile/blacken-docs
     rev: v1.10.0
     hooks:
     -   id: blacken-docs
         additional_dependencies: [black]
--   repo: https://gitlab.com/PyCQA/flake8
-    rev: 3.9.0
+-   repo: https://github.com/PyCQA/flake8
+    rev: 3.9.1
     hooks:
     -   id: flake8
         additional_dependencies: [