Add workaround for macOS High Sierra installer creation (#144)

Author: ninxsoft

Mist/Helpers/InstallerCreator.swift

@@ -41,6 +41,14 @@ enum InstallerCreator {
             ["installer", "-pkg", packageURL.path, "-target", mountPoint.path]
         ]
 
+        // workaround for macOS High Sierra
+        if installer.version.range(of: "^10\\.13\\.", options: .regularExpression) != nil {
+            argumentsArrays += [
+                ["ditto", "/Applications/Install \(installer.name).app", "\(mountPoint.path)/Applications/Install \(installer.name).app"],
+                ["rm", "-r", "/Applications/Install \(installer.name).app"]
+            ]
+        }
+
         if installer.catalinaOrNewer {
             argumentsArrays += [
                 ["ditto", "\(mountPoint.path)Applications", "\(mountPoint.path)/Applications"],