Fixes: Reset timeline preview variables

What's Changed

• fix: reset timeline preview variables when not found by @nadeem-cs in #291
• chore: update changelog by @nadeem-cs in #293
• fix: added npm token to github release pipeline by @vkalta in #270
• chore: update version to 3.24.3 in package-lock.json by @harshithad0703 in #296
• Update README.md by @myWorkshop123 in https://github.com/contentstack/contentstack-javascript/pull/262\

New Contributors

• @myWorkshop123 made their first contribution in #262

Full Changelog: v3.24.2...v3.24.3