Support nltk>=3.9 to fix vulnerability

See:
- Root cause issue: https://github.com/nltk/nltk/issues/3266
- Breaking change when using "punkt_tab" instead of "punkt": https://github.com/nltk/nltk/issues/3293

meteor.py

@@ -120,7 +120,9 @@ class Meteor(evaluate.Metric):
  import nltk
 
  nltk.download("wordnet")
- if NLTK_VERSION >= version.Version("3.6.5"):
+ if NLTK_VERSION >= version.Version("3.9.0"):
+ nltk.download("punkt_tab")
+ elif NLTK_VERSION >= version.Version("3.6.5"):
  nltk.download("punkt")
  if NLTK_VERSION >= version.Version("3.6.6"):
  nltk.download("omw-1.4")