chore(deps): bump the actions-infrastructure group with 2 updates

Bumps the actions-infrastructure group with 2 updates: [actions/upload-artifact](https://github.com/actions/upload-artifact) and [actions/download-artifact](https://github.com/actions/download-artifact).


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

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

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions-infrastructure
- dependency-name: actions/download-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions-infrastructure
...

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

Author: dependabot[bot]

.github/workflows/test.yml

@@ -54,12 +54,12 @@ jobs:
       - name: Build git archive
         run: mkdir archive && git archive -v -o archive/nibabel-archive.tgz HEAD
       - name: Upload sdist and wheel artifacts
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v5
         with:
           name: dist
           path: dist/
       - name: Upload git archive artifact
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v5
         with:
           name: archive
           path: archive/
@@ -73,13 +73,13 @@ jobs:
     steps:
       - name: Download sdist and wheel artifacts
         if: matrix.package != 'archive'
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: dist
           path: dist/
       - name: Download git archive artifact
         if: matrix.package == 'archive'
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: archive
           path: archive/
@@ -251,7 +251,7 @@ jobs:
           files: cov.xml
           token: ${{ secrets.CODECOV_TOKEN }}
       - name: Upload pytest test results
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v5
         with:
           name: pytest-results-${{ matrix.os }}-${{ matrix.python-version }}-${{ matrix.dependencies }}-${{ matrix.architecture }}
           path: test-results.xml
@@ -288,7 +288,7 @@ jobs:
       id-token: write
     if: github.event_name == 'push' && startsWith(github.ref, 'refs/tags/')
     steps:
-      - uses: actions/download-artifact@v5
+      - uses: actions/download-artifact@v6
         with:
           name: dist
           path: dist/