Allow pubspec key 'funding' (#3529)

lib/src/validator/pubspec_typo.dart

diff --git a/lib/src/validator/pubspec_typo.dart b/lib/src/validator/pubspec_typo.dart
index 0843bc4..f92a894 100644
--- a/lib/src/validator/pubspec_typo.dart
+++ b/lib/src/validator/pubspec_typo.dart
@@ -68,4 +68,5 @@
   'flutter',
   'screenshots',
   'platforms',
+  'funding',
 ];