Add `merge` function and enable union operator between `Configuration` instances / applicable source types #286

	name: Test package

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

	jobs:
	check:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v4
	- uses: pdm-project/setup-pdm@v4
	with:
	python-version: '3.13'
	cache: true
	- name: Install check dependencies
	run: pdm install --group check
	- name: Run checks
	run: pdm run check
	test:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	python-version: ['3.8', '3.9', '3.10', '3.11', '3.12', '3.13', 'pypy-3.8', 'pypy-3.9', 'pypy-3.10']
	steps:
	- uses: actions/checkout@v4
	- uses: pdm-project/setup-pdm@v4
	with:
	python-version: ${{ matrix.python-version }}
	cache: true
	- name: Install test dependencies
	run: pdm install --group test
	- name: Run tests
	run: pdm run test

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