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@v0.1.0...v1.15.0)

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

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

pyproject.toml

@@ -65,7 +65,7 @@ dependencies = [
 ]
 
 optional-dependencies.develop = [
-  "mypy<1.15",
+  "mypy<1.16",
   "poethepoet<0.32",
   "pyproject-fmt<2.6",
   "ruff<0.10",