bump version to 5.2.0

-## NEXT
+## 5.2.0
 * This release requires Flutter 3.22.0 and Dart 3.4.
 
 * [Android] Fixed a leak of the barcode scanner.

@@ -4,7 +4,7 @@
 #
 Pod::Spec.new do |s|
   s.name             = 'mobile_scanner'
-  s.version          = '5.1.1'
+  s.version          = '5.2.0'
   s.summary          = 'An universal scanner for Flutter based on MLKit.'
   s.description      = <<-DESC
 An universal scanner for Flutter based on MLKit.

@@ -4,7 +4,7 @@
 #
 Pod::Spec.new do |s|
   s.name             = 'mobile_scanner'
-  s.version          = '5.1.1'
+  s.version          = '5.2.0'
   s.summary          = 'An universal scanner for Flutter based on MLKit.'
   s.description      = <<-DESC
 An universal scanner for Flutter based on MLKit.

 name: mobile_scanner
 description: A universal barcode and QR code scanner for Flutter based on MLKit. Uses CameraX on Android, AVFoundation on iOS and Apple Vision & AVFoundation on macOS.
-version: 5.1.1
+version: 5.2.0
 repository: https://github.com/juliansteenbakker/mobile_scanner
 
 screenshots: