Fix compilation with Swift 5.5

Author: Frizlab

Sources/DummySendable.swift

@@ -2,7 +2,10 @@ import Foundation
 import os
 
 
-#if swift(>=5.5)
+/* Sendable exists from Swift 5.5, however OSLog is only Sendable starting from Xcode with at least Swift 5.8.
+ * That being said, the Sendability issues regarding OSLog not being Sendable only trigger errors when compiling with Swift 5.5 exactly,
+ *  so we cheat and make a dummy Sendable protocol for Swift 5.5 too. */
+#if swift(>=5.6)
 public protocol GHALogger_Sendable : Sendable {}
 #else
 public protocol GHALogger_Sendable {}