update README with enableJavaScript info (#2766)

diff --git a/packages/url_launcher/url_launcher/CHANGELOG.md b/packages/url_launcher/url_launcher/CHANGELOG.md
index 3d8dd24..56b4bb3 100644
--- a/packages/url_launcher/url_launcher/CHANGELOG.md
+++ b/packages/url_launcher/url_launcher/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 5.4.9
+
+* Update README.
+
 ## 5.4.8
 
 * Initialize `previousAutomaticSystemUiAdjustment` in launch method.
diff --git a/packages/url_launcher/url_launcher/README.md b/packages/url_launcher/url_launcher/README.md
index 4b65cfa..2dcc635 100644
--- a/packages/url_launcher/url_launcher/README.md
+++ b/packages/url_launcher/url_launcher/README.md
@@ -70,6 +70,8 @@
 
 ## Browser vs In-app Handling
 By default, Android opens up a browser when handling URLs. You can pass
-forceWebView: true parameter to tell the plugin to open a WebView instead. On
+`forceWebView: true` parameter to tell the plugin to open a WebView instead. 
+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.
diff --git a/packages/url_launcher/url_launcher/pubspec.yaml b/packages/url_launcher/url_launcher/pubspec.yaml
index c09dcbf..a019859 100644
--- a/packages/url_launcher/url_launcher/pubspec.yaml
+++ b/packages/url_launcher/url_launcher/pubspec.yaml
@@ -2,7 +2,7 @@
 description: Flutter plugin for launching a URL on Android and iOS. Supports
   web, phone, SMS, and email schemes.
 homepage: https://github.com/flutter/plugins/tree/master/packages/url_launcher/url_launcher
-version: 5.4.8
+version: 5.4.9
 
 flutter:
   plugin: