Use built-in isoformat support #339

	name: CI

	on: [push, pull_request, workflow_dispatch]

	jobs:
	tests:
	runs-on: ubuntu-20.04
	strategy:
	matrix:
	python-version: [3.6, 3.7, 3.8, 3.9, "3.10", "3.11"]
	fail-fast: false
	steps:
	- uses: actions/checkout@v4

	- name: Set up Python ${{ matrix.python-version }}
	uses: actions/setup-python@v5
	with:
	python-version: ${{ matrix.python-version }}

	- name: Install dependencies
	run: \|
	sudo apt update
	sudo apt-get install -y libxml2-dev libxmlsec1-dev
	python -m pip install --upgrade pip
	pip install .[test]

	- name: Run tests
	run: \|
	python -m unittest tests.tests

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