fixing mutable dataclass attribute error by using default_factory #401

	name: Test

	on:
	push:
	branches: [main]
	pull_request:
	branches: [main]

	jobs:
	build:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2
	- name: Set up Python 3.9
	uses: actions/setup-python@v2
	with:
	python-version: 3.9
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	pip install black flake8 pytest
	pip install -r requirements.txt
	pip install .
	- name: Check code style with Black
	run: \|
	black -l 80 --check map_machine tests
	- name: Lint with Flake8
	run: \|
	flake8 --max-line-length=80 --ignore=E203,W503
	- name: Test with pytest
	run: \|
	pytest -v
	build-windows:
	runs-on: windows-latest
	steps:
	- uses: actions/checkout@v2
	- name: Set up Python 3.9
	uses: actions/setup-python@v2
	with:
	python-version: 3.9
	- name: Install dependencies
	run: \|
	python -m pip install --upgrade pip
	pip install black flake8 pytest
	pip install -r requirements.txt
	pip install .
	- name: Check code style with Black
	run: \|
	black -l 80 --check map_machine setup.py tests
	- name: Lint with Flake8
	run: \|
	flake8 --max-line-length=80 --ignore=E203,W503
	- name: Test render
	run: \|
	map-machine render -b 10.000,20.000,10.001,20.001 --cache tests/data

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