Bump actions/upload-artifact from 3 to 4 (#27)

* Bump actions/upload-artifact from 3 to 4

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 3 to 4.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v3...v4)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

* Update actions/download-artifact as well

---------

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: pdmurray <[email protected]>

.github/workflows/build.yml

@@ -44,7 +44,7 @@ jobs:
         pip uninstall -y "jupyterlab-skip-traceback" jupyterlab
 
     - name: Upload extension packages
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: extension-artifacts
         path: dist/jupyterlab_skip_traceback*
@@ -62,7 +62,7 @@ jobs:
       with:
         python-version: '3.9'
         architecture: 'x64'
-    - uses: actions/download-artifact@v3
+    - uses: actions/download-artifact@v4
       with:
         name: extension-artifacts
     - name: Install and Test