Add thread safety note on README #617

	name: test
	on: [push]

	env:
	LIBZIM_DL_VERSION: "9.1.0"
	MACOSX_DEPLOYMENT_TARGET: "12.0"

	jobs:
	lint:
	runs-on: ubuntu-22.04
	steps:
	- uses: actions/checkout@v3

	- name: Set up Python ${{ matrix.python }}
	uses: actions/setup-python@v4
	with:
	python-version: "3.12"
	architecture: x64

	- name: Check formatting and linting
	run: \|
	pip install -U invoke
	invoke install-dev
	invoke check

	test:
	runs-on: ${{ matrix.os }}
	strategy:
	matrix:
	os: [ubuntu-22.04, macos-13]
	python: ["3.8", "3.9", "3.10", "3.11", "3.12"]

	steps:
	- uses: actions/checkout@v3

	- name: Set up Python ${{ matrix.python }}
	uses: actions/setup-python@v4
	with:
	python-version: ${{ matrix.python }}
	architecture: x64

	- name: Installing dependencies
	run: pip install -U pip setuptools build

	- name: Building & installing for tests (with profiling)
	env:
	PROFILE: 1
	run: pip install -e .

	- name: Testing
	run: \|
	pip install pytest pytest-cov cython
	py.test --cov=libzim --cov-report=term --cov-report term-missing .

	- name: Upload coverage report to codecov
	if: matrix.os == 'ubuntu-22.04' && matrix.python == '3.11'
	uses: codecov/codecov-action@v3
	with:
	token: ${{ secrets.CODECOV_TOKEN }}

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