feat(router): support the "oneOf" directive (#2246)

Used reference: graphql/graphql-spec#825

Author: ysmolski

README.md

@@ -23,8 +23,8 @@ WunderGraph Cosmo is a comprehensive Lifecycle API Management platform tailored
 
 ## The State of GraphQL Federation 2024
 
-Get insights from industry experts and Federation practicioners across all industries and learn how companies are using GraphQL Federation.
-Head over to the [State of GraphQL Federation 2024](https://wundergraph.com/state-of-graphql-federation/2024) page and download the full **48 page PDF report** for free!
+Get insights from industry experts and Federation practitioners across all industries and learn how companies are using GraphQL Federation.
+Head over to the [State of GraphQL Federation 2024](https://wundergraph.com/state-of-graphql-federation/2024) page and download the full **48-page PDF report** for free!
 
 ### Why Federated GraphQL?
 

demo/pkg/subgraphs/employees/subgraph/generated/generated.go

@@ -33,6 +33,7 @@ type Query {
   products: [Products!]!
   teammates(team: Department!): [Employee!]!
   firstEmployee: Employee! @tag(name: "internal")
+  findEmployeesBy(criteria: FindEmployeeCriteria!): [Employee!]!
 }
 
 scalar Upload
@@ -191,3 +192,9 @@ type SDK implements IProduct @key(fields: "upc") {
   owner: Employee!
   unicode: String!
 }
+
+input FindEmployeeCriteria @oneOf {
+    id: Int
+    department: Department
+    title: String
+}