Add condition to Save nuget package as artifact step to run only on windows-latest

* Add `if: matrix.os == 'windows-latest'` condition to the `Save nuget package as artifact` step

Author: gdziadkiewicz

.github/workflows/main.yml

@@ -34,6 +34,7 @@ jobs:
       run: ./build.sh
       shell: bash
     - name: Save nuget package as artifact
+      if: matrix.os == 'windows-latest'
       uses: actions/upload-artifact@v4
       with:
         name: nuget-package