[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/PyCQA/flake8: 4.0.1 → 5.0.4](PyCQA/flake8@4.0.1...5.0.4)
- [github.com/asottile/pyupgrade: v2.34.0 → v2.37.3](asottile/pyupgrade@v2.34.0...v2.37.3)
- [github.com/pre-commit/mirrors-mypy: v0.961 → v0.971](pre-commit/mirrors-mypy@v0.961...v0.971)

Author: pre-commit-ci[bot]

.pre-commit-config.yaml

@@ -9,7 +9,7 @@ repos:
       - id: check-added-large-files
       - id: debug-statements
   - repo: https://github.com/PyCQA/flake8
-    rev: "4.0.1"
+    rev: "5.0.4"
     hooks:
       - id: flake8
         additional_dependencies: [flake8-import-order, flake8-bugbear]
@@ -23,12 +23,12 @@ repos:
       - id: isort
         name: isort (python)
   - repo: https://github.com/asottile/pyupgrade
-    rev: v2.34.0
+    rev: v2.37.3
     hooks:
     -   id: pyupgrade
         args: [--py37-plus]
   - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: "v0.961"
+    rev: "v0.971"
     hooks:
       - id: mypy
         files: vdirsyncer/.*