fix pickWeb

app/pubspec.lock

@@ -84,7 +84,7 @@ packages:
       name: ffi
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.3"
+    version: "1.0.0"
   file:
     dependency: transitive
     description:
@@ -98,7 +98,7 @@ packages:
       name: file_picker
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "3.0.0-nullsafety.2"
+    version: "3.0.0"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -124,7 +124,7 @@ packages:
       name: flutter_keyboard_visibility_platform_interface
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.0-nullsafety.0"
+    version: "2.0.0"
   flutter_keyboard_visibility_web:
     dependency: transitive
     description:
@@ -232,28 +232,28 @@ packages:
       name: path_provider_linux
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.0.1+2"
+    version: "2.0.0"
   path_provider_macos:
     dependency: transitive
     description:
       name: path_provider_macos
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.0.4+8"
+    version: "2.0.0"
   path_provider_platform_interface:
     dependency: transitive
     description:
       name: path_provider_platform_interface
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.4"
+    version: "2.0.1"
   path_provider_windows:
     dependency: transitive
     description:
       name: path_provider_windows
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.0.4+3"
+    version: "2.0.0"
   pedantic:
     dependency: transitive
     description:
@@ -281,7 +281,7 @@ packages:
       name: plugin_platform_interface
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0-nullsafety.2"
+    version: "2.0.0"
   process:
     dependency: transitive
     description:
@@ -440,14 +440,14 @@ packages:
       name: win32
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.7.4+1"
+    version: "2.0.0"
   xdg_directories:
     dependency: transitive
     description:
       name: xdg_directories
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.2"
+    version: "0.2.0"
   zone_local:
     dependency: transitive
     description:
@@ -456,5 +456,5 @@ packages:
     source: hosted
     version: "0.1.2"
 sdks:
-  dart: ">=2.12.0-259.9.beta <3.0.0"
+  dart: ">=2.12.0 <3.0.0"
   flutter: ">=1.24.0-10.2.pre"

lib/widgets/toolbar.dart

@@ -567,6 +567,7 @@ class _ImageButtonState extends State<ImageButton> {
     } else {
       // User canceled the picker
     }
+    return null;
   }
 
   @override