Adding git ignores and pubspec updates (#166)

platform_design/.gitignore

@@ -59,6 +59,7 @@
 **/ios/Flutter/app.flx
 **/ios/Flutter/app.zip
 **/ios/Flutter/flutter_assets/
+**/ios/Flutter/flutter_export_environment.sh
 **/ios/ServiceDefinitions.json
 **/ios/Runner/GeneratedPluginRegistrant.*
 

platform_design/pubspec.lock

@@ -7,7 +7,7 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.3.0"
+    version: "2.4.0"
   boolean_selector:
     dependency: transitive
     description:
@@ -94,7 +94,7 @@ packages:
       name: quiver
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.5"
+    version: "2.1.2+1"
   sky_engine:
     dependency: transitive
     description: flutter