Add missing how-to/external-routing.md #281

	name: lint-and-test

	concurrency:
	group: ${{ github.ref }}
	cancel-in-progress: true

	on:
	pull_request:
	push:
	branches: [master]

	jobs:
	lint:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v3
	- uses: actions/setup-python@v3
	- uses: pre-commit/action@v3.0.0

	test-build:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v3
	- uses: actions/setup-python@v4
	with:
	python-version: "3.10"
	cache: "pip"

	- name: Install Python requirements
	run: pip install -r requirements.txt

	- name: Build documentation
	run: mkdocs build
	env:
	DEFAULT_LANGUAGE_ONLY: true

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