Add x-yorkie-user-agent (#67)

Sources/Core/Auth.swift

@@ -40,6 +40,7 @@ class AuthClientInterceptor<Request, Response>: ClientInterceptor<Request, Respo
                 header.add(name: "authorization", value: token)
             }
 
+            header.add(name: "x-yorkie-user-agent", value: "yorkie-ios-sdk/\(yorkieVersion)")
             part = .metadata(header)
         default:
             break

Sources/Core/Client.swift

@@ -205,12 +205,7 @@ public actor Client {
 
         let channel = builder.connect(host: rpcAddress.host, port: rpcAddress.port)
 
-        let authInterceptors: AuthClientInterceptors?
-        if options.apiKey != nil || options.token != nil {
-            authInterceptors = AuthClientInterceptors(apiKey: options.apiKey, token: options.token)
-        } else {
-            authInterceptors = nil
-        }
+        let authInterceptors = AuthClientInterceptors(apiKey: options.apiKey, token: options.token)
 
         self.rpcClient = YorkieServiceAsyncClient(channel: channel, interceptors: authInterceptors)
         self.eventStream = PassthroughSubject()

Sources/Version.swift

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2023 The Yorkie Authors. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import Foundation
+
+let yorkieVersion = "0.3.3"