docs: remove irrelevant changelog entry (#627)

## Summary
- Remove the tar security vulnerability entry from the changelog as it
relates to the website dependency, not the Python client itself.

## Test plan
- [x] Verify the changelog no longer contains the irrelevant entry
- [x] No code changes, documentation only

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: vdusek

CHANGELOG.md

@@ -10,7 +10,6 @@ All notable changes to this project will be documented in this file.
 
 ### 🐛 Bug Fixes
 
-- Resolve tar security vulnerability in website ([#600](https://github.com/apify/apify-client-python/pull/600)) ([3087d6b](https://github.com/apify/apify-client-python/commit/3087d6b557afec5fe846a8a9e4f73ff4cbc2ebe2)) by [@B4nan](https://github.com/B4nan)
 - Prevent infinite loop in _wait_for_finish on persistent 404s ([#619](https://github.com/apify/apify-client-python/pull/619)) ([00e8621](https://github.com/apify/apify-client-python/commit/00e86213227631b9ea3d39e8f9d736e9a9b028f1)) by [@vdusek](https://github.com/vdusek)
 - Remove erroneous async keyword from sync ActorClient.default_build ([#620](https://github.com/apify/apify-client-python/pull/620)) ([b2b1103](https://github.com/apify/apify-client-python/commit/b2b110364ddd97640268fe6b6727273d0e1739d5)) by [@vdusek](https://github.com/vdusek)
 - Use explicit None checks for client config to respect zero values ([#623](https://github.com/apify/apify-client-python/pull/623)) ([416fd98](https://github.com/apify/apify-client-python/commit/416fd98d54b5ba9535afe157dcc354464c902ed5)) by [@vdusek](https://github.com/vdusek)