Bump nltk from 3.6.6 to 3.9.2 in /OCR_To_Google_Question_Papers (#492)

Bumps [nltk](https://github.com/nltk/nltk) from 3.6.6 to 3.9.2.
- [Changelog](https://github.com/nltk/nltk/blob/develop/ChangeLog)
- [Commits](nltk/nltk@3.6.6...3.9.2)

---
updated-dependencies:
- dependency-name: nltk
  dependency-version: 3.9.2
  dependency-type: direct:production
...

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Author: dependabot[bot]

OCR_To_Google_Question_Papers/requirements.txt

@@ -11,7 +11,7 @@ jieba3k==0.35.1
 joblib==1.2.0
 lxml==4.6.3
 newspaper3k==0.2.8
-nltk==3.6.6
+nltk==3.9.2
 Pillow==7.2.0
 pytesseract==0.3.5
 python-dateutil==2.8.1