Bump express from 4.18.2 to 4.21.0 #92

	name: Flake8
	on: [push]
	jobs:
	build:
	runs-on: ubuntu-latest
	strategy:
	fail-fast: false
	matrix:
	python-version: [3.11]

	steps:
	# git checkout
	- uses: actions/checkout@v2

	# python setup
	- name: Set up Python ${{ matrix.python-version }}
	uses: actions/setup-python@v1
	with:
	python-version: ${{ matrix.python-version }}

	# python cache
	- uses: actions/cache@v1
	with:
	path: ~/.cache/pip
	key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
	restore-keys: \|
	${{ runner.os }}-pip-

	# install flake8
	- name: install flake8
	run: pip install flake8

	# run flake8
	- name: run flake8
	run: flake8 src/ setup.py

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