Bump mypy from 0.670 to 0.700 (#62)

Bumps [mypy](https://github.com/python/mypy) from 0.670 to 0.700.
- [Release notes](https://github.com/python/mypy/releases)
- [Commits](python/mypy@v0.670...v0.700)

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

Author: dependabot[bot]

poetry.lock

@@ -36,7 +36,7 @@ python = "^3.6"
 typing-extensions = "^3.7"
 
 [tool.poetry.dev-dependencies]
-mypy = "^0.670"
+mypy = "^0.700"
 wemake-python-styleguide = "^0.7.0"
 flake8-pytest = "^1.3"
 flake8-pyi = "^19.2"