[url_launcher] Update readme for URL schemes on iOS (flutter#3252)

Author: TahaTesser

packages/url_launcher/url_launcher/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 6.0.3
+
+* Updat README notes about URL schemes on iOS
+
 ## 6.0.2
 
 * Update platform_plugin_interface version requirement.

packages/url_launcher/url_launcher/README.md

@@ -8,6 +8,22 @@ iOS, Android, web, Windows, macOS, and Linux.
 ## Usage
 To use this plugin, add `url_launcher` as a [dependency in your pubspec.yaml file](https://flutter.dev/platform-plugins/).
 
+## Installation
+
+### iOS 
+Add any URL schemes passed to `canLaunch` as `LSApplicationQueriesSchemes` entries in your Info.plist file.
+
+Example:  
+```
+<key>LSApplicationQueriesSchemes</key>
+<array>
+  <string>https</string>
+  <string>http</string>
+</array>
+```
+
+See [`-[UIApplication canOpenURL:]`](https://developer.apple.com/documentation/uikit/uiapplication/1622952-canopenurl) for more details.
+
 ### Example
 
 ``` dart
@@ -97,4 +113,4 @@ By default, Android opens up a browser when handling URLs. You can pass
 If you do this for a URL of a page containing JavaScript, make sure to pass in
 `enableJavaScript: true`, or else the launch method will not work properly. On
 iOS, the default behavior is to open all web URLs within the app. Everything
-else is redirected to the app handler.
+else is redirected to the app handler.

packages/url_launcher/url_launcher/pubspec.yaml

@@ -2,7 +2,7 @@ name: url_launcher
 description: Flutter plugin for launching a URL. Supports
   web, phone, SMS, and email schemes.
 homepage: https://github.com/flutter/plugins/tree/master/packages/url_launcher/url_launcher
-version: 6.0.2
+version: 6.0.3
 
 flutter:
   plugin: