chore(deps): update mypy requirement from ==1.15.* to ==1.16.*

Updates the requirements on [mypy](https://github.com/python/mypy) to permit the latest version.
- [Changelog](https://github.com/python/mypy/blob/master/CHANGELOG.md)
- [Commits](python/mypy@v1.15.0...v1.16.0)

---
updated-dependencies:
- dependency-name: mypy
  dependency-version: 1.16.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

requirements-testing.txt

@@ -6,4 +6,4 @@ pytest-xdist == 3.7.*
 types-PyYAML ~= 6.0
 black == 25.*
 ruff == 0.11.*
-mypy == 1.15.*
+mypy == 1.16.*