Bump nltk from 3.2.5 to 3.6.6 in /NLP/FreeTransfer-X

Bumps [nltk](https://github.com/nltk/nltk) from 3.2.5 to 3.6.6.
- [Release notes](https://github.com/nltk/nltk/releases)
- [Changelog](https://github.com/nltk/nltk/blob/develop/ChangeLog)
- [Commits](nltk/nltk@3.2.5...3.6.6)

---
updated-dependencies:
- dependency-name: nltk
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

NLP/FreeTransfer-X/pip-requirements.txt

@@ -1,6 +1,6 @@
 numpy==1.18.0
 pythainlp==2.3.2
-nltk==3.2.5
+nltk==3.6.6
 subword-nmt==0.3.7
 mecab-python3==1.0.4
 unidic-lite==1.0.8