⬆️ Bump handlebars from 4.7.6 to 4.7.7 - #57

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: koj-co/delete-merged-action@master, pascalgn/automerge-action@v0.13.1. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/