upgrade packages (#41)

pubspec.yaml

@@ -10,16 +10,16 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
-  http: ^1.1.0
-  shared_preferences: ^2.0.15
+  http: ^1.2.0
+  shared_preferences: ^2.2.2
   universal_io: ^2.0.4
-  connectivity_plus: ^5.0.1
-  device_info_plus: ^9.0.2
-  package_info_plus: ^4.2.0
-  image_picker: ^1.0.5
+  connectivity_plus: ^5.0.2
+  device_info_plus: ^9.1.1
+  package_info_plus: ^5.0.1
+  image_picker: ^1.0.7
   mime: ^1.0.4
   intl: ^0.19.0
-  flutter_markdown: ^0.6.18+2
+  flutter_markdown: ^0.6.18+3
 
 dev_dependencies:
   flutter_test: