[pre-commit.ci] pre-commit autoupdate

updates:
- git://github.com/pre-commit/pre-commit-hooks: v2.5.0 → v4.0.1
- https://gitlab.com/pycqa/flake8 → https://github.com/PyCQA/flake8
- [github.com/PyCQA/flake8: 3.8.1 → 3.9.2](PyCQA/flake8@3.8.1...3.9.2)
- [github.com/psf/black: 19.10b0 → 21.9b0](psf/black@19.10b0...21.9b0)
- [github.com/pre-commit/pygrep-hooks: v1.5.1 → v1.9.0](pre-commit/pygrep-hooks@v1.5.1...v1.9.0)

.pre-commit-config.yaml

@@ -2,7 +2,7 @@ exclude: '^docs/conf.py'
 
 repos:
 - repo: git://github.com/pre-commit/pre-commit-hooks
-  rev: v2.5.0
+  rev: v4.0.1
   hooks:
   - id: trailing-whitespace
   - id: check-added-large-files
@@ -17,17 +17,17 @@ repos:
   - id: check-merge-conflict
   - id: mixed-line-ending
     args: ['--fix=no']
--   repo: https://gitlab.com/pycqa/flake8
-    rev: '3.8.1'  # pick a git hash / tag to point to
+-   repo: https://github.com/PyCQA/flake8
+    rev: '3.9.2'  # pick a git hash / tag to point to
     hooks:
     -   id: flake8
         additional_dependencies:
           - flake8-rst-docstrings
 -   repo: https://github.com/psf/black
-    rev: 19.10b0
+    rev: 21.9b0
     hooks:
     - id: black
 -   repo: https://github.com/pre-commit/pygrep-hooks
-    rev: v1.5.1
+    rev: v1.9.0
     hooks:
       - id: rst-backticks