add docker compose setup for swift 5.8 (#129)

motivation: prepare for swift 5.8

changes:
* update use of Locks to address NIO warnings
* update docker compose setup to use release version of 5.7
* add docker compose setup for 5.8

Author: tomerd

Tests/LifecycleTests/Helpers.swift

@@ -13,7 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 import Foundation
-import Lifecycle
+@testable import Lifecycle
 import NIO
 import NIOConcurrencyHelpers
 
@@ -25,7 +25,7 @@ class GoodItem: LifecycleTask {
     let shutdownDelay: Double
 
     var state = State.idle
-    let stateLock = Lock()
+    let stateLock = Lifecycle.Lock()
 
     init(id: String = UUID().uuidString,
          startDelay: Double = Double.random(in: 0.01 ... 0.1),
@@ -67,7 +67,7 @@ class NIOItem {
     let shutdownDelay: Int64
 
     var state = State.idle
-    let stateLock = Lock()
+    let stateLock = Lifecycle.Lock()
 
     init(eventLoopGroup: EventLoopGroup,
          id: String = UUID().uuidString,

docker/docker-compose.2004.57.yaml

@@ -6,7 +6,8 @@ services:
     image: swift-service-lifecycle:20.04-5.7
     build:
       args:
-        base_image: "swiftlang/swift:nightly-main-focal"
+        ubuntu_version: "focal"
+        swift_version: "5.7"
 
   test:
     image: swift-service-lifecycle:20.04-5.7

docker/docker-compose.2004.58.yaml

@@ -0,0 +1,19 @@
+version: "3"
+
+services:
+
+  runtime-setup:
+    image: swift-service-lifecycle:20.04-5.8
+    build:
+      args:
+        ubuntu_version: "focal"
+        swift_version: "5.8"
+
+  test:
+    image: swift-service-lifecycle:20.04-5.8
+    environment:
+      - SKIP_SIGNAL_TEST=true
+      - FORCE_TEST_DISCOVERY=--enable-test-discovery
+
+  shell:
+    image: swift-service-lifecycle:20.04-5.8