fix:(deps-dev): update mypy requirement

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@v0.971...v1.8.0)

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

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

pyproject.toml

@@ -47,7 +47,7 @@ dev = [
     "myst-parser>=0.18.0",
     "flake8>=6.0.0",
     "docformatter>=1.4.0,<1.7.6",
-    "mypy>=0.971,<1.8",
+    "mypy>=0.971,<1.9",
     "pytest-xdist>=3.0.2",
     "pre-commit>=2.20.0,<3.7.0",
 ]