[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/asottile/pyupgrade: v2.12.0 → v2.13.0](https://github.com/asottile/pyupgrade/compare/v2.12.0...v2.13.0)
- [github.com/asottile/reorder_python_imports: v2.4.0 → v2.5.0](https://github.com/asottile/reorder_python_imports/compare/v2.4.0...v2.5.0)
- [github.com/psf/black: 20.8b1 → 21.4b0](https://github.com/psf/black/compare/20.8b1...21.4b0)

.pre-commit-config.yaml

 repos:
   - repo: https://github.com/asottile/pyupgrade
-    rev: v2.12.0
+    rev: v2.13.0
     hooks:
       - id: pyupgrade
         args: ["--py36-plus"]
   - repo: https://github.com/asottile/reorder_python_imports
-    rev: v2.4.0
+    rev: v2.5.0
     hooks:
       - id: reorder-python-imports
         name: Reorder Python imports (src, tests)
         files: "^(?!examples/)"
         args: ["--application-directories", "src"]
   - repo: https://github.com/psf/black
-    rev: 20.8b1
+    rev: 21.4b0
     hooks:
       - id: black
   - repo: https://github.com/PyCQA/flake8