Update draft-pdf.yml

bumped `actions/upload-artifact@v4` from `v3` which is [recently deprecated](https://github.blog/changelog/2024-04-16-deprecation-notice-v3-of-the-artifact-actions/)

Author: samueldmcdermott

.github/workflows/draft-pdf.yml

@@ -19,7 +19,7 @@ jobs:
           # This should be the path to the paper within your repo.
           paper-path: paper/paper.md
       - name: Upload
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: paper
           # This is the output path where Pandoc will write the compiled