Lint

ci: add golangci-lint GitHub Actions workflow #3

	name: Lint

	on:
	pull_request:
	branches: [ main ]

	jobs:
	lint:
	name: Markdown and Go
	runs-on: ubuntu-latest
	permissions:
	# Required: allow read access to the content for analysis.
	contents: read
	steps:

	- name: Check out code into the Go module directory
	uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2

	- name: Set up Go
	uses: actions/setup-go@4a3601121dd01d1626a1e23e37211e3254c1c06c # v6.4.0
	with:
	go-version-file: go.mod

	- name: Go formatting
	run: \|
	if [ -z "$(gofmt -l .)" ]; then
	echo -e "All '*.go' files are properly formatted."
	else
	echo -e "Please run 'make lint' to fix. Some files need formatting:"
	gofmt -d -l .
	exit 1
	fi

	- name: Read golangci-lint version from Makefile
	id: lint-version
	run: echo "version=$(grep -oP 'GOLANGCI_LINT_VERSION\s=\s\K\S+' Makefile)" >> $GITHUB_OUTPUT

	# https://github.com/golangci/golangci-lint-action?tab=readme-ov-file#verify
	- name: Verify linter configuration and Lint go code
	uses: golangci/golangci-lint-action@1e7e51e771db61008b38414a730f564565cf7c20 # v9.2.0
	with:
	verify: true
	args: --timeout=30m
	version: ${{ steps.lint-version.outputs.version }}

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