Fix warnings, that appeared after requiring Swift 5.4 (#2085)

Author: fabianfett

Package.swift

@@ -43,39 +43,49 @@ var targets: [PackageDescription.Target] = [
             dependencies: ["CNIOAtomics"]),
     .target(name: "NIOHTTP1",
             dependencies: ["NIO", "NIOCore", "NIOConcurrencyHelpers", "CNIOHTTPParser"]),
-    .target(name: "NIOEchoServer",
-            dependencies: ["NIOPosix", "NIOCore", "NIOConcurrencyHelpers"]),
-    .target(name: "NIOEchoClient",
-            dependencies: ["NIOPosix", "NIOCore", "NIOConcurrencyHelpers"]),
-    .target(name: "NIOHTTP1Server",
-            dependencies: ["NIOPosix", "NIOCore", "NIOHTTP1", "NIOConcurrencyHelpers"]),
-    .target(name: "NIOHTTP1Client",
-            dependencies: ["NIOPosix", "NIOCore", "NIOHTTP1", "NIOConcurrencyHelpers"]),
+    .executableTarget(name: "NIOEchoServer",
+                      dependencies: ["NIOPosix", "NIOCore", "NIOConcurrencyHelpers"],
+                      exclude: ["README.md"]),
+    .executableTarget(name: "NIOEchoClient",
+                      dependencies: ["NIOPosix", "NIOCore", "NIOConcurrencyHelpers"],
+                      exclude: ["README.md"]),
+    .executableTarget(name: "NIOHTTP1Server",
+                      dependencies: ["NIOPosix", "NIOCore", "NIOHTTP1", "NIOConcurrencyHelpers"],
+                      exclude: ["README.md"]),
+    .executableTarget(name: "NIOHTTP1Client",
+                      dependencies: ["NIOPosix", "NIOCore", "NIOHTTP1", "NIOConcurrencyHelpers"],
+                      exclude: ["README.md"]),
     .target(name: "CNIOHTTPParser"),
     .target(name: "NIOTLS", dependencies: ["NIO", "NIOCore"]),
-    .target(name: "NIOChatServer",
-            dependencies: ["NIOPosix", "NIOCore", "NIOConcurrencyHelpers"]),
-    .target(name: "NIOChatClient",
-            dependencies: ["NIOPosix", "NIOCore", "NIOConcurrencyHelpers"]),
+    .executableTarget(name: "NIOChatServer",
+                      dependencies: ["NIOPosix", "NIOCore", "NIOConcurrencyHelpers"],
+                      exclude: ["README.md"]),
+    .executableTarget(name: "NIOChatClient",
+                      dependencies: ["NIOPosix", "NIOCore", "NIOConcurrencyHelpers"],
+                      exclude: ["README.md"]),
     .target(name: "NIOWebSocket",
             dependencies: ["NIO", "NIOCore", "NIOHTTP1", "CNIOSHA1"]),
-    .target(name: "NIOWebSocketServer",
-            dependencies: ["NIOPosix", "NIOCore", "NIOHTTP1", "NIOWebSocket"]),
-    .target(name: "NIOWebSocketClient",
-            dependencies: ["NIOPosix", "NIOCore", "NIOHTTP1", "NIOWebSocket"]),
-    .target(name: "NIOPerformanceTester",
+    .executableTarget(name: "NIOWebSocketServer",
+                      dependencies: ["NIOPosix", "NIOCore", "NIOHTTP1", "NIOWebSocket"],
+                      exclude: ["README.md"]),
+    .executableTarget(name: "NIOWebSocketClient",
+                      dependencies: ["NIOPosix", "NIOCore", "NIOHTTP1", "NIOWebSocket"],
+                      exclude: ["README.md"]),
+    .executableTarget(name: "NIOPerformanceTester",
             dependencies: ["NIOPosix", "NIOCore", "NIOEmbedded", "NIOHTTP1", "NIOFoundationCompat", "NIOWebSocket"]),
-    .target(name: "NIOMulticastChat",
-            dependencies: ["NIOPosix", "NIOCore"]),
-    .target(name: "NIOUDPEchoServer",
-            dependencies: ["NIOPosix", "NIOCore"]),
-    .target(name: "NIOUDPEchoClient",
+    .executableTarget(name: "NIOMulticastChat",
             dependencies: ["NIOPosix", "NIOCore"]),
+    .executableTarget(name: "NIOUDPEchoServer",
+                      dependencies: ["NIOPosix", "NIOCore"],
+                      exclude: ["README.md"]),
+    .executableTarget(name: "NIOUDPEchoClient",
+                      dependencies: ["NIOPosix", "NIOCore"],
+                      exclude: ["README.md"]),
     .target(name: "NIOTestUtils",
             dependencies: ["NIOPosix", "NIOCore", "NIOEmbedded", "NIOHTTP1"]),
-    .target(name: "NIOCrashTester",
+    .executableTarget(name: "NIOCrashTester",
             dependencies: ["NIOPosix", "NIOCore", "NIOEmbedded", "NIOHTTP1", "NIOWebSocket", "NIOFoundationCompat"]),
-    .target(name: "NIOAsyncAwaitDemo",
+    .executableTarget(name: "NIOAsyncAwaitDemo",
             dependencies: ["NIOPosix", "NIOCore", "NIOHTTP1"]),
     .testTarget(name: "NIOCoreTests",
                 dependencies: ["NIOCore"]),