Update mypy requirement from ~=1.0 to ~=1.1

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@v1.0.0...v1.1.1)

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

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

requirements/dev.txt

@@ -1,7 +1,7 @@
 # development dependencies (see docs.txt for documentation building dependencies)
 # linting and static type-checking
 flake8>=3.7.7, <7.0.0
-mypy~= 1.0
+mypy~= 1.1
 types-requests>=2.25.0, <3.0.0
 # testing
 pytest>=5.3.5, <8.0.0