Add notes about manually installing sndfile and install it on CI #10

	name: Build & test

	on: [push]

	jobs:
	build:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	python-version: ['3.7', '3.8', '3.9', '3.10', '3.11']
	steps:
	- uses: actions/checkout@v2
	- name: Set up Python
	uses: actions/setup-python@v2
	with:
	python-version: ${{ matrix.python-version }}
	- name: Display Python version
	run: python -c "import sys; print(sys.version)"
	- uses: FedericoCarboni/setup-ffmpeg@v2
	id: setup-ffmpeg
	- name: Check FFMpeg
	run: ffmpeg -version
	- name: Manually install sndfile
	run: sudo apt install libsndfile1
	- name: Install
	run: pip install -e .[dev,test,docs]
	- name: Run tests
	run: python tests/unit_tests.py

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