Update actions/upload-artifact action to v7 (#12)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/continuous.yml

@@ -39,7 +39,7 @@ jobs:
           dotnet pack src/MudBlazor.FontIcons.MaterialIcons/MudBlazor.FontIcons.MaterialIcons.csproj --configuration Release --no-build --output artifacts/packages
           dotnet pack src/MudBlazor.FontIcons.MaterialSymbols/MudBlazor.FontIcons.MaterialSymbols.csproj --configuration Release --no-build --output artifacts/packages
       - name: Publish packages artifact
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         with:
           name: packages
           path: artifacts/packages

.github/workflows/release.yml

@@ -59,7 +59,7 @@ jobs:
       - name: Push to GitHub Packages
         run: dotnet nuget push "artifacts/packages/*.nupkg" --source "https://nuget.pkg.github.com/${{ github.repository_owner }}/index.json" --api-key "${{ secrets.GITHUB_TOKEN }}" --skip-duplicate
       - name: Publish packages artifact
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         with:
           name: packages
           path: artifacts/packages