Bump nltk from 3.8.1 to 3.9 in /Oracle-23ai-RAG-Chatbot

Bumps [nltk](https://github.com/nltk/nltk) from 3.8.1 to 3.9.
- [Changelog](https://github.com/nltk/nltk/blob/develop/ChangeLog)
- [Commits](nltk/nltk@3.8.1...3.9)

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

Signed-off-by: dependabot[bot] <support@github.com>

Oracle-23ai-RAG-Chatbot/requirements.txt

@@ -131,7 +131,7 @@ nbconvert==7.16.2
 nbformat==5.10.2
 nest-asyncio==1.6.0
 networkx==3.2.1
-nltk==3.8.1
+nltk==3.9
 notebook_shim==0.2.4
 numba==0.59.0
 numpy==1.26.4