add PKCE to SessionRefresh middleware and refactor #123

	name: mozilla-django-oidc codecov
	on: [pull_request]

	jobs:
	codecov:
	runs-on: ubuntu-latest
	name: Codecov
	steps:
	- name: Checkout repository
	uses: actions/checkout@v2
	- name: Setup python
	uses: actions/setup-python@v2
	with:
	python-version: '3.12'
	- name: Install dependencies
	run: pip install codecov tox tox-gh-actions
	- name: Run tox
	run: tox
	- uses: codecov/codecov-action@v1
	with:
	verbose: true

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