Update .gitignore

Author: Rad Azzouz

.gitignore

@@ -85,4 +85,5 @@ unlinked_spec.ds
 !**/ios/**/default.mode2v3
 !**/ios/**/default.pbxuser
 !**/ios/**/default.perspectivev3
-!/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
+!/packages/flutter_tools/test/data/dart_dependencies_test/**/.packages
+/example/ios/Flutter/flutter_export_environment.sh