Split out libraries into SPM packages (#298)

Sources/Secretive/Preview Content/PreviewUpdater.swift

@@ -0,0 +1,29 @@
+import Foundation
+import Combine
+import Brief
+
+class PreviewUpdater: UpdaterProtocol {
+
+    let update: Release?
+    let testBuild = false
+
+    init(update: Update = .none) {
+        switch update {
+        case .none:
+            self.update = nil
+        case .advisory:
+            self.update = Release(name: "10.10.10", prerelease: false, html_url: URL(string: "https://example.com")!, body: "Some regular update")
+        case .critical:
+            self.update = Release(name: "10.10.10", prerelease: false, html_url: URL(string: "https://example.com")!, body: "Critical Security Update")
+        }
+    }
+
+}
+
+extension PreviewUpdater {
+
+    enum Update {
+        case none, advisory, critical
+    }
+
+}