[stable8] chore: Add .tgz files generated by 'npm pack' to .gitignore

[backportbot]

Backport of PR #8463

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 46.53%. Comparing base (329ad3e) to head (d8977c9).
⚠️ Report is 6 commits behind head on stable8.

Additional details and impacted files

@@           Coverage Diff            @@
##           stable8    #8466   +/-   ##
========================================
  Coverage    46.53%   46.53%           
========================================
  Files          194      194           
  Lines         4891     4891           
  Branches      1263     1201   -62     
========================================
  Hits          2276     2276           
- Misses        2527     2529    +2     
+ Partials        88       86    -2     

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