Update release-nuget.yaml

Author: davidjgoss

.github/workflows/release-nuget.yaml

@@ -15,7 +15,7 @@ jobs:
       - name: Setup .NET
         uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: 6.0.x
+          dotnet-version: 8.0.x
       - uses: cucumber/[email protected]
         with:
           nuget-api-key: ${{ secrets.NUGET_API_KEY }}