[pre-commit.ci] pre-commit autoupdate

updates:
- [github.com/pre-commit/mirrors-mypy: v0.990 → v0.991](pre-commit/mirrors-mypy@v0.990...v0.991)

Author: pre-commit-ci[bot]

.pre-commit-config.yaml

@@ -27,6 +27,6 @@ repos:
     -   id: pyupgrade
         args: [--py37-plus]
   - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: 'v0.990'
+    rev: 'v0.991'
     hooks:
     -   id: mypy