fix NIO deprecations & update to secure versions

Author: weissi

Diff for: Package.swift

@@ -21,8 +21,8 @@ let package = Package(
         .library(name: "AsyncHTTPClient", targets: ["AsyncHTTPClient"]),
     ],
     dependencies: [
-        .package(url: "https://github.com/apple/swift-nio.git", from: "2.10.1"),
-        .package(url: "https://github.com/apple/swift-nio-ssl.git", from: "2.0.0"),
+        .package(url: "https://github.com/apple/swift-nio.git", from: "2.11.0"),
+        .package(url: "https://github.com/apple/swift-nio-ssl.git", from: "2.4.1"),
         .package(url: "https://github.com/apple/swift-nio-extras.git", from: "1.3.0"),
     ],
     targets: [

Diff for: Sources/AsyncHTTPClient/HTTPClient.swift

@@ -48,7 +48,7 @@ public class HTTPClient {
     public let eventLoopGroup: EventLoopGroup
     let eventLoopGroupProvider: EventLoopGroupProvider
     let configuration: Configuration
-    let isShutdown = Atomic<Bool>(value: false)
+    let isShutdown = NIOAtomic<Bool>.makeAtomic(value: false)
 
     /// Create an `HTTPClient` with specified `EventLoopGroup` provider and configuration.
     ///