Bump actions/upload-artifact from 5 to 6

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v5...v6)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/pr-review-listener.yml

@@ -13,7 +13,7 @@ jobs:
       - name: Save PR number
         run: echo "${{ github.event.pull_request.number }}" > pr.txt
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           # unique name: includes workflow run id
           name: pr-number-${{ github.run_id }}

.github/workflows/unit-tests.yml

@@ -139,7 +139,7 @@ jobs:
           fastfetch
 
       - name: "Upload test summary"
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: test-${{ matrix.server.id }}-${{ matrix.server.os }}
           path: test