⬆️ Bump actions/upload-artifact from 2 to 4 (#324)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 2 to 4.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v2...v4)

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

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/cache.yml

@@ -22,13 +22,13 @@ jobs:
         run: |
           jb build lectures --path-output ./ -W --keep-going
       - name: Upload Execution Reports
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         if: failure()
         with:
           name: execution-reports
           path: _build/html/reports
       - name: Upload "_build" folder (cache)
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: build-cache
           path: _build