Add a Read the Docs configuration file. #41

	name: CI

	on: [push, pull_request]

	jobs:
	test:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	# There is no "allow failures" option for GitHub Actions, but
	# we test on the latest LTS release anyway just so we can
	# notice if it breaks.
	#
	#
	# Version 12.2.0 added `Module#createRequire(...)`, which
	# ESLint depends upon. (TODO: Consider using ESLint someday.)
	#
	# Versions 14.18.1 and 16.13.0 are the two most recent LTS
	# versions at the time of writing, and we intend to support
	# them both. Some Webpack users may be using 14.18.1 because
	# of (questionable?) advice to downgrade past
	# Node.js version 16 to work around a hashing algorithm
	# deprecation:
	#
	# https://stackoverflow.com/questions/69394632/webpack-build-failing-with-err-ossl-evp-unsupported
	#
	# Version 17 is the latest major version as of this writing.
	# We intend to support it, but it has no LTS releases yet, and
	# we may not reasonably be able to support it if it introduces
	# major regressions.
	#
	node-version: ["12.2.0", "14.18.1", "16.13.0", "17", "lts/*"]
	steps:
	- name: Checkout
	uses: actions/checkout@v2
	- name: Set up Node.js
	uses: actions/setup-node@v2
	with:
	cache: npm
	node-version: ${{ matrix.node-version }}
	- name: Check the Node.js version
	run: node --version
	- name: Install npm dependencies
	run: npm install
	- name: Clean
	run: npm run clean
	# PORT TODO: Consider adding a linting step.
	- name: Build
	run: npm run build
	- name: Run unit tests
	run: npm test

Provide feedback