chore: LEAP-1365: Bump NLTK to address CVE

[robot-ci-heartex]

Hi @jombooth!

This PR was created in a response to PRs in upstream repos:

• chore: LEAP-1365: Bump NLTK to address CVE label-studio-sdk#272

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.76%. Comparing base (898276b) to head (c8d348b).
Report is 243 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #6186      +/-   ##
===========================================
- Coverage    76.77%   76.76%   -0.01%     
===========================================
  Files          168      168              
  Lines        13650    13650              
===========================================
- Hits         10480    10479       -1     
- Misses        3170     3171       +1     

Flag	Coverage Δ
pytests	76.76% <ø> (-0.01%)	⬇️

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