Update .gitignore to new dart_tool pub cache (flutter#19)

bcko · kevmoo · commit 239b7e20da76 · 2019-03-26T09:28:24.000-07:00
dart-lang/sdk#32030
diff --git a/.gitignore b/.gitignore
@@ -1,3 +1,4 @@
 .packages
+.dart_tool/
 .pub/
 pubspec.lock
