Bump nltk from 3.6.2 to 3.6.6 in /mitremap-notebook (#184)

Bumps [nltk](https://github.com/nltk/nltk) from 3.6.2 to 3.6.6.
- [Release notes](https://github.com/nltk/nltk/releases)
- [Changelog](https://github.com/nltk/nltk/blob/develop/ChangeLog)
- [Commits](nltk/nltk@3.6.2...3.6.6)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Ian Hellen <ianhelle@microsoft.com>

mitremap-notebook/requirements-stable.txt

@@ -79,7 +79,7 @@ nbconvert==7.2.1
 nbformat==5.7.0
 nest-asyncio==1.5.6
 networkx==2.8.7
-nltk==3.6.2
+nltk==3.6.6
 notebook==6.4.12
 numba==0.56.2
 numpy==1.23.3

mitremap-notebook/requirements.txt

@@ -2,6 +2,6 @@ ipywidgets==7.5.1
 transformers==4.5.1
 torch==1.10.2
 msticpy==2.1.2
-nltk==3.6.2
+nltk==3.6.6
 iocextract==1.13.1
 shap==0.41.0