Revert "Drop iOS 14 and macOS 11 support"

This reverts commit dcef7f47ff.

Vendor/RefreshControl/RefreshControlModifier.swift

@@ -0,0 +1,46 @@
+//
+//  RefreshControlModifier.swift
+//  SwiftUI_Pull_to_Refresh
+//
+//  Created by Geri Borbás on 18/09/2021.
+//
+
+import Foundation
+import SwiftUI
+
+struct RefreshControlModifier: ViewModifier {
+    @State private var geometryReaderFrame: CGRect = .zero
+    let refreshControl: RefreshControl
+
+    internal init(onValueChanged: @escaping (UIRefreshControl) -> Void) {
+        refreshControl = RefreshControl(onValueChanged: onValueChanged)
+    }
+
+    func body(content: Content) -> some View {
+        if #available(iOS 15.0, macOS 12.0, tvOS 15.0, *) {
+            return content
+        } else {
+            return content
+                .background(
+                    GeometryReader { geometry in
+                        ScrollViewMatcher(
+                            onResolve: { scrollView in
+                                refreshControl.add(to: scrollView)
+                            },
+                            geometryReaderFrame: $geometryReaderFrame
+                        )
+                        .preference(key: FramePreferenceKey.self, value: geometry.frame(in: .global))
+                        .onPreferenceChange(FramePreferenceKey.self) { frame in
+                            self.geometryReaderFrame = frame
+                        }
+                    }
+                )
+        }
+    }
+}
+
+extension View {
+    func refreshControl(onValueChanged: @escaping (_ refreshControl: UIRefreshControl) -> Void) -> some View {
+        modifier(RefreshControlModifier(onValueChanged: onValueChanged))
+    }
+}