Avoid `RemovedInSphinx80Warning` in path-manipulation code. (#977) #913

	name: unit tests
	on: [push, pull_request]
	jobs:
	build:

	runs-on: ubuntu-latest
	strategy:
	fail-fast: false
	matrix:
	python-version: ['3.7', '3.8', '3.9', '3.10']
	sphinx-version:
	- '4.0.3'
	- '4.1.2'
	- '4.2.0'
	- '4.3.2'
	- '4.5.0'
	- '5.0.2'
	- '5.1.1'
	- '5.3.0'
	- '6.1.3'
	- git+https://github.com/sphinx-doc/sphinx.git@master
	exclude:
	# avoid bug in following configurations
	# sphinx/util/typing.py:37: in <module>
	# from types import Union as types_Union
	# ImportError: cannot import name 'Union' from 'types'
	- python-version: '3.10'
	sphinx-version: '4.0.3'
	- python-version: '3.10'
	sphinx-version: '4.1.2'

	# Sphinx has removed support for Python 3.7, Breathe will follow.
	- python-version: '3.7'
	sphinx-version: git+https://github.com/sphinx-doc/sphinx.git@master
	- python-version: '3.7'
	sphinx-version: '6.1.3'

	steps:
	- uses: actions/checkout@v2
	- uses: actions/cache@v1
	with:
	path: ~/.cache/pip
	key: ${{ runner.os }}-pip-${{ hashFiles('requirements/*.txt') }}
	restore-keys: \|
	${{ runner.os }}-pip-
	- name: set up python ${{ matrix.python-version }}
	uses: actions/setup-python@v1
	with:
	python-version: ${{ matrix.python-version }}

	- name: install sphinx from PyPI or from git
	run: \|
	if echo "${{ matrix.sphinx-version }}"\|grep -q git; then
	pip install ${{ matrix.sphinx-version }}
	else
	pip install -Iv Sphinx==${{ matrix.sphinx-version }}
	fi

	- name: install dependencies
	run: \|
	pip install -r requirements/development.txt

	- name: run the unit tests
	run: make dev-test

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