update qr reader, fix crashes on android 6

Closes #1

verification/lib/home_page.dart

@@ -379,10 +379,10 @@ class _HomePageState extends State<HomePage> {
     _qrController = controller;
     _lastResult = '';
     controller.scannedDataStream.listen((scanData) {
-      if (scanData.code.isNotEmpty && !_disconnected) {
+      if ((scanData.code?.isNotEmpty ?? false) && !_disconnected) {
         if (_lastResult != scanData.code) {
           _qrResult = scanData;
-          _lastResult = _qrResult!.code;
+          _lastResult = _qrResult!.code!;
           _bloc!.onAdd(_lastResult);
         }
       }

verification/pubspec.lock

@@ -213,7 +213,7 @@ packages:
       name: path_provider_android
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.7"
+    version: "2.0.8"
   path_provider_ios:
     dependency: transitive
     description:
@@ -283,13 +283,27 @@ packages:
       name: qr_code_scanner
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.5.2"
+    version: "0.6.1"
   shared_preferences:
     dependency: "direct main"
     description:
       name: shared_preferences
       url: "https://pub.dartlang.org"
     source: hosted
+    version: "2.0.9"
+  shared_preferences_android:
+    dependency: transitive
+    description:
+      name: shared_preferences_android
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.8"
+  shared_preferences_ios:
+    dependency: transitive
+    description:
+      name: shared_preferences_ios
+      url: "https://pub.dartlang.org"
+    source: hosted
     version: "2.0.8"
   shared_preferences_linux:
     dependency: transitive
@@ -365,7 +379,7 @@ packages:
       name: url_launcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "6.0.13"
+    version: "6.0.15"
   url_launcher_linux:
     dependency: transitive
     description:

verification/pubspec.yaml

@@ -16,7 +16,7 @@ dependencies:
   path_provider: ^2.0.3
   bloc: ^7.1.0
   flutter_bloc: ^7.2.0
-  qr_code_scanner: ^0.5.2
+  qr_code_scanner: ^0.6.1
   flutter_phoenix: ^1.0.0
   shared_preferences: ^2.0.8
   connectivity: ^3.0.6