Revert "Drop iOS 14 and macOS 11 support"

This reverts commit dcef7f47ff.

Backports/Badge+Backport.swift

@@ -0,0 +1,15 @@
+import SwiftUI
+
+extension Backport where Content: View {
+    @ViewBuilder func badge(_ count: Text?) -> some View {
+        #if os(tvOS)
+            content
+        #else
+            if #available(iOS 15.0, macOS 12.0, tvOS 15.0, *) {
+                content.badge(count)
+            } else {
+                content
+            }
+        #endif
+    }
+}