Bump mypy from 1.4.1 to 1.5.0

Bumps [mypy](https://github.com/python/mypy) from 1.4.1 to 1.5.0.
- [Commits](python/mypy@v1.4.1...v1.5.0)

---
updated-dependencies:
- dependency-name: mypy
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

requirements-mypy.txt

@@ -1,6 +1,6 @@
 typing
 # Mypy requires typed-ast, which is broken on PyPy 3.7 (could work in PyPy 3.8).
-mypy==1.4.1; implementation_name == "cpython"
+mypy==1.5.0; implementation_name == "cpython"
 types-simplejson
 types-certifi
 types-requests