build: Add sass:icons step to nextcloud dev build - #150

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: webiny/action-conventional-commits@8bc41ff4e7d423d56fa4905f6ff79209a78776c7. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/