Bump tornado from 6.3.3 to 6.4.1 in /docs #520

	# This workflow will install Python dependencies, run tests and lint with a single version of Python
	# For more information see: https://help.github.com/actions/language-and-framework-guides/using-python-with-github-actions

	name: Python application

	on: [push]

	jobs:
	build:

	runs-on: ubuntu-latest

	steps:
	- uses: actions/checkout@v2
	- name: Set up Python 3.9
	uses: actions/setup-python@v2
	with:
	python-version: 3.9
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	pip install flake8 pytest pytest-cov isort black requests
	if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
	- name: Check with isort
	run: isort strongtyping --check-only
	- name: Lint with black
	run: python -m black strongtyping --check
	- name: Test with pytest
	run: \|
	pytest strongtyping --cov=strongtyping
	- name: Run coverage
	run: \|
	codecov --token=${{ secrets.CODECOV_TOKEN }}

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