add 'requires newer protocol version' error code #554

	on:
	pull_request:
	push:
	branches:
	- main

	jobs:
	check:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2

	- name: Read Tool Versions
	id: tool-versions
	run: echo "::set-output name=nodejs::$(sed -nr 's/nodejs ([0-9]+)/\1/p' .tool-versions)"

	- uses: actions/setup-node@v2
	with:
	node-version: ${{ steps.tool-versions.outputs.nodejs }}

	# Using git grep to fail the build if any tab characters are found in source files (except Go files) - we use spaces for whitespace.
	# Using prettier (format:data:check) to ensure JSON and YAML files have consistent formatting.
	- run: \|
	! git --no-pager grep $'\t' -- './*' ':!./go' \|\| { echo 'ERROR: Lint failed! Source files must use spaces for whitespace.'; false; }
	npm ci
	npm run lint
	npm test

	check-go:
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v2

	- name: Read Tool Versions
	id: tool-versions
	run: echo "::set-output name=golang::$(sed -nr 's/golang ([0-9]+)/\1/p' .tool-versions)"

	- name: Setup Go
	uses: actions/setup-go@v2
	with:
	go-version: ${{ steps.tool-versions.outputs.golang }}

	- name: Build for Go users
	run: scripts/build-go.sh

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