Add: nuget into pipeline

.gitea/workflows/build-debian-package.yml

@@ -20,6 +20,9 @@ jobs:
         uses: actions/setup-dotnet@v4
         with:
           dotnet-version: "10.0.x"
+      - uses: nuget/setup-nuget@v2
+        with:
+          nuget-version: '6.x'
       - name: "Build .deb"
         run: ./run-build.sh "${{ gitea.ref_name }}" "./alumnihub_10.0_amd64"
       - name: "Upload .deb"