Fix NuGet action

Author: bdukes

.github/workflows/ci.yml

@@ -35,7 +35,7 @@
                 },
                 {
                     "name": "Setup NuGet",
-                    "uses": "actions/setup-nuget@v1.1.1",
+                    "uses": "nuget/setup-nuget@v1.1.1",
                     "with": {
                         "nuget-version": "6.x"
                     }