Fixed Safemode Schema query

Author: joadan

src/Linq2GraphQL.Client/GraphClient.cs

@@ -73,7 +73,7 @@ public async Task<GraphQLSchema> GetSchemaForSafeModeAsync()
         {
             var executor = new QueryExecutor<GraphQLSchema>(this);
 
-            var graphRequest = new GraphQLRequest { Query = Helpers.SchemaQuery };
+            var graphRequest = new GraphQLRequest { Query = Helpers.SchemaQueryIncludeDeprecated };
             return await executor.ExecuteRequestAsync("__schema", graphRequest);
         });
     }

src/Linq2GraphQL.Client/Schema/Helpers.cs

@@ -12,4 +12,15 @@ internal static class Helpers
                                             }
                                           }
                                         }";
+
+    internal const string SchemaQueryIncludeDeprecated = @"{
+                                          __schema {
+                                            types {
+                                              name
+                                              fields(includeDeprecated: true) {
+                                                name
+                                              }
+                                            }
+                                          }
+                                        }";
 }