ci: bump actions/upload-artifact from 4 to 5 (#26)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 4 to 5.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v4...v5)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/build.yml

@@ -47,7 +47,7 @@ jobs:
           make html
       - name: Upload HTML
         id: upload
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v5
         with:
           name: ndn-packet-spec-html
           path: _build/html
@@ -71,7 +71,7 @@ jobs:
           export SOURCE_DATE_EPOCH="$(git log -1 --format=%ct)"
           make latexpdf
       - name: Upload PDF
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v5
         with:
           name: ndn-packet-spec-pdf
           path: _build/latex/ndn-packet-spec.pdf