Upgrade setup-node action to version 6 (#148)

## Description

Describe your changes here.

Fixes #Issue_Number (if available)

### Ensure that your pull request has followed all the steps below:
- [ ] Code compilation
- [ ] Created tests which fail without the change (if possible)
- [ ] All tests passing
- [ ] Extended the README / documentation, if necessary

Author: BenjaminMichaelis

.github/actions/setup-node/action.yml

@@ -9,7 +9,7 @@ runs:
   using: 'composite'
   steps:
     - name: Set up Node.js
-      uses: actions/setup-node@v4
+      uses: actions/setup-node@v6
       with:
         node-version: '20'
         cache: 'npm'