Bump actions/download-artifact from 5 to 6

Bumps [actions/download-artifact](https://github.com/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/download-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/dotnet-build.yml

@@ -209,13 +209,13 @@ jobs:
           dotnet-quality: 'ga'
 
       - name: Download NuGet List
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: nuget-list
           path: ./
 
       - name: Download Package List
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: packages
           path: ./packages
@@ -262,7 +262,7 @@ jobs:
           dotnet-quality: 'ga'
 
       - name: Download signed packages for ${{ matrix.platform }}
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: signed-packages
           path: ./packages