Update readme

Author: myfknoll

README.md

@@ -33,7 +33,7 @@ Window         |  Web
 ## Getting started
 
 ```dart
-simple_barcode_scanner: ^0.3.0
+simple_barcode_scanner: ^0.3.1
 
 ```   
 Import the library:

example/pubspec.lock

@@ -214,7 +214,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "0.3.2"
+    version: "0.3.1"
   sky_engine:
     dependency: transitive
     description: flutter