Update upload-pages-artifact to v5 (#765)

* Update upload-pages-artifact to v5

* Apply suggestion from @kratz00

Co-authored-by: Steffen Pankratz <kratz00@gmx.de>

---------

Co-authored-by: Steffen Pankratz <kratz00@gmx.de>

Author: ArBridgeman

.github/workflows/gh-pages.yml

@@ -1,3 +1,12 @@
 # Unreleased
 
 ## Summary
+
+This release includes an update of `action/upload-pages-artifact` from v4 to v5. With this
+change, now all actions used in the PTB run with Node.js 24. This is important as support
+for Node.js 20 reaches it end-of-life in April of 2026 and support for it in GitHub will end in
+September 2026; for more details, see GitHub's [deprecation notice](https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/).
+
+## Refactoring
+
+* #764: Updated `action/upload-pages-artifact` from v4 to [v5](https://github.com/actions/upload-pages-artifact/releases/tag/v5.0.0)

doc/changes/unreleased.md

@@ -32,7 +32,7 @@ jobs:
 
       - name: Upload Artifact
         id: upload-artifact
-        uses: actions/upload-pages-artifact@v4
+        uses: actions/upload-pages-artifact@v5
         with:
           path: html-documentation