ci: try to fix error of pushing package.

.github/workflows/release.yml

@@ -56,4 +56,4 @@ jobs:
         path: './temp'
 
     - name: Push LLamaSharp packages to nuget.org
-      run: dotnet nuget push ./temp/LLamaSharp*.nupkg --source https://www.nuget.org -k "$NUGET_API_TOKEN" --skip-duplicate
+      run: dotnet nuget push ./temp/LLamaSharp*.nupkg --source https://www.nuget.org -k ${{ secrets.LLAMA_SHARP_NUGET_KEY }} --skip-duplicate