upgrade iOS SDK version to 9.3

ios/Podfile

@@ -1,5 +1,5 @@
 # Uncomment this line to define a global platform for your project
-platform :ios, '9.0'
+platform :ios, '9.3'
 
 # CocoaPods analytics sends network stats synchronously affecting flutter build latency.
 ENV['COCOAPODS_DISABLE_STATS'] = 'true'

ios/Runner.xcodeproj/project.pbxproj

@@ -476,7 +476,7 @@
 					"$(PROJECT_DIR)/Flutter",
 				);
 				INFOPLIST_FILE = Runner/Info.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.3;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				LIBRARY_SEARCH_PATHS = (
 					"$(inherited)",
@@ -610,7 +610,7 @@
 					"$(PROJECT_DIR)/Flutter",
 				);
 				INFOPLIST_FILE = Runner/Info.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.3;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				LIBRARY_SEARCH_PATHS = (
 					"$(inherited)",
@@ -645,7 +645,7 @@
 					"$(PROJECT_DIR)/Flutter",
 				);
 				INFOPLIST_FILE = Runner/Info.plist;
-				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.3;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				LIBRARY_SEARCH_PATHS = (
 					"$(inherited)",