Bump mypy from 1.20.0 to 1.20.1 in /requirements/lintrunner

Bumps [mypy](https://github.com/python/mypy) from 1.20.0 to 1.20.1.
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v1.20.0...v1.20.1)

---
updated-dependencies:
- dependency-name: mypy
  dependency-version: 1.20.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements/lintrunner/requirements.txt

@@ -3,7 +3,7 @@ lintrunner-adapters>=0.8.0
 # RUFF, RUFF-FIX
 ruff==0.15.9
 # MYPY
-mypy==1.20.0
+mypy==1.20.1
 types-PyYAML==6.0.12.20250822
 # EDITORCONFIG-CHECKER
 editorconfig-checker==3.6.1