Remove dependency on _NIOConcurrency (#229)

Author: fabianfett

Package.swift

@@ -13,7 +13,7 @@ let package = Package(
         .library(name: "AWSLambdaTesting", targets: ["AWSLambdaTesting"]),
     ],
     dependencies: [
-        .package(url: "https://github.com/apple/swift-nio.git", .upToNextMajor(from: "2.32.0")),
+        .package(url: "https://github.com/apple/swift-nio.git", .upToNextMajor(from: "2.33.0")),
         .package(url: "https://github.com/apple/swift-log.git", .upToNextMajor(from: "1.4.2")),
         .package(url: "https://github.com/swift-server/swift-backtrace.git", .upToNextMajor(from: "1.2.3")),
     ],
@@ -30,7 +30,6 @@ let package = Package(
             .product(name: "NIOCore", package: "swift-nio"),
             .product(name: "NIOConcurrencyHelpers", package: "swift-nio"),
             .product(name: "NIOPosix", package: "swift-nio"),
-            .product(name: "_NIOConcurrency", package: "swift-nio"),
         ]),
         .testTarget(name: "AWSLambdaRuntimeCoreTests", dependencies: [
             .byName(name: "AWSLambdaRuntimeCore"),

Sources/AWSLambdaRuntimeCore/Lambda.swift

@@ -18,7 +18,6 @@ import Glibc
 import Darwin.C
 #endif
 
-import _NIOConcurrency
 import Backtrace
 import Logging
 import NIOCore

Sources/AWSLambdaRuntimeCore/LambdaHandler.swift

@@ -12,7 +12,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-import _NIOConcurrency
 import Dispatch
 import NIOCore
 

Sources/AWSLambdaTesting/Lambda+Testing.swift

@@ -36,7 +36,6 @@
 // }
 
 #if swift(>=5.5)
-import _NIOConcurrency
 import AWSLambdaRuntime
 import AWSLambdaRuntimeCore
 import Dispatch