fix: upgrade mypy #537

	name: format

	on: [push, pull_request]

	jobs:
	format:
	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v1

	- name: Set up Python
	uses: actions/setup-python@v1
	with:
	python-version: 3.8

	- name: Install dependencies
	run: pip3 install .[dev]

	- name: Run --version
	run: oj --version

	- name: Run pylint
	run: pylint --rcfile=setup.cfg onlinejudge_command tests setup.py

	- name: Run isort
	run: isort --check-only --diff onlinejudge_command tests setup.py

	- name: Run yapf
	run: yapf --diff --recursive onlinejudge_command tests setup.py

	- name: Run mypy
	run: mypy onlinejudge_command tests setup.py

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