fixed an error in the readme (#2980) #3999

	name: XGBoost Tests

	on: [push, pull_request]

	jobs:
	test:
	strategy:
	max-parallel: 4
	fail-fast: false
	matrix:
	python-version: ['3.7', '3.8', '3.9']
	platform: [ubuntu-latest]

	runs-on: ${{ matrix.platform }}

	steps:
	- uses: actions/checkout@v3
	- name: Set up Python ${{ matrix.python-version }}
	uses: actions/setup-python@v4
	with:
	python-version: ${{ matrix.python-version }}
	- name: Install other dependencies
	run: \|
	python -m pip install -U pip setuptools wheel
	python -m pip install -U "Cython<3.0"
	pip install .
	pip install -r requirements/requirements-test.txt
	pip install -r requirements/requirements-rotbaum.txt
	pip install -r requirements/requirements-rotbaum-extra-methods.txt
	- name: Test with pytest
	run: \|
	pytest -n2 --timeout 120 --doctest-modules test/ext/rotbaum

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