refactor: use shared http client for delete req

Author: iwa

Examples/DeleteJSON/DeleteJSON.swift

@@ -6,7 +6,7 @@ import NIOFoundationCompat
 @main
 struct DeleteJSON {
     static func main() async throws {
-        let httpClient = HTTPClient(eventLoopGroupProvider: .singleton)
+        let httpClient = HTTPClient.shared
 
         do {
             var request = HTTPClientRequest(url: "http://localhost:8080/todos/1)")
@@ -17,7 +17,5 @@ struct DeleteJSON {
         } catch {
             print("request failed:", error)
         }
-        // it is important to shutdown the httpClient after all requests are done, even if one failed
-        try await httpClient.shutdown()
     }
 }