chore: sync files readme

Author: terovirtanen

.github/workflows/sync-files-README.md

@@ -0,0 +1,13 @@
+# 🚀 Files sync workflow
+
+This workflow synchronizes files between Github repositories.
+
+## 📋 Configuration
+
+- **.github/sync.yml** This is a configuration file to synchronize action.
+- **OrganizationToken** This is the name of Github app used to provide synchronization token credentials.
+
+## 📚 Usage Instructions
+
+This is an action to synchronize files from this repository to other Github repositories. It uses BetaHuhn [repo-file-sync-action](https://github.com/BetaHuhn/repo-file-sync-action) for synchronization. Configuration details can be found there.
+