Modernize examples #2757

	name: tests

	on:
	pull_request:
	push:
	branches: master

	jobs:
	build:

	runs-on: ubuntu-latest
	strategy:
	matrix:
	python-version: [3.8, 3.9, '3.10', 3.11, 3.12]

	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 dependencies
	run: \|
	python -m pip install --upgrade pip
	pip install -r requirements.txt
	pip install .
	- name: Run flake8
	run: \|
	flake8 skfem
	- name: Run sphinx build
	run: \|
	sphinx-build -W -a -b html docs docs/_build
	- name: Run sphinx doctests
	run: \|
	sphinx-build -W -a -b doctest docs docs/_build
	- name: Run mypy
	run: \|
	mypy skfem
	- name: Run pytest
	run: \|
	pytest

Provide feedback