Error return value of `io.WriteString` is not checked (errcheck)

issues found

The following actions uses Node.js version which is deprecated and will be forced to run on node20: actions/checkout@v3, actions/setup-go@v4, golangci/golangci-lint-action@v3. For more info: https://github.blog/changelog/2024-03-07-github-actions-all-actions-will-run-on-node20-instead-of-node16-by-default/