Use marp-cli:latest instead of pinned v4

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: codebytes

.github/workflows/marp-pages.yml

@@ -34,14 +34,14 @@ jobs:
           cp -R slides/themes build/themes
 
       - name: Marp Build (HTML)
-        uses: docker://marpteam/marp-cli:v4
+        uses: docker://marpteam/marp-cli:latest
         with:
           args: --theme-set slides/themes -o build/index.html --html -- slides/Slides.md
         env:
           MARP_USER: root:root
 
       - name: Marp Build (PDF)
-        uses: docker://marpteam/marp-cli:v4
+        uses: docker://marpteam/marp-cli:latest
         with:
           args: --theme-set slides/themes -o build/Slides.pdf --html --allow-local-files -- slides/Slides.md
         env: