Update mypy requirement from ^0.950 to ^0.960

Updates the requirements on [mypy](https://github.com/python/mypy) to permit the latest version.
- [Release notes](https://github.com/python/mypy/releases)
- [Commits](python/mypy@v0.950...v0.960)

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

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

pyproject.toml

@@ -43,7 +43,7 @@ black = "^22.1.0"
 flake8 = "^4.0.1"
 pytest = "^7.0.1"
 pytest-cov = "^3.0.0"
-mypy = "^0.950"
+mypy = "^0.960"
 pytest-mock = "^3.7.0"
 flake8-isort = "^4.1.1"
 asyncmock = {version = "^0.4.2", python = "<3.8"}