build(deps): 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/ci.yml

@@ -92,7 +92,7 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v5
 
-      - uses: actions/download-artifact@v5
+      - uses: actions/download-artifact@v6
         with:
           name: ${{ env.NUGET_PACKAGES_ARTIFACT }}
           path: ${{ env.NUGET_DIRECTORY }}
@@ -161,7 +161,7 @@ jobs:
           dotnet-version: |
             9.0.x
 
-      - uses: actions/download-artifact@v5
+      - uses: actions/download-artifact@v6
         with:
           name: ${{ env.NUGET_PACKAGES_ARTIFACT }}
           path: ${{ env.NUGET_DIRECTORY }}
@@ -275,7 +275,7 @@ jobs:
     permissions:
       id-token: write
     steps:
-      - uses: actions/download-artifact@v5
+      - uses: actions/download-artifact@v6
         with:
           name: ${{ env.NUGET_PACKAGES_ARTIFACT }}
           path: ${{ env.NUGET_DIRECTORY }}