chore(deps): Bump dawidd6/action-download-artifact from 21 to 23 - #405

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: whelk-io/maven-settings-xml-action@9dc09b23833fa9aa7f27b63db287951856f3433d. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/