chore: Add external contributor to CHANGELOG.md (#17725)

This PR adds the external contributor to the CHANGELOG.md file, so that
they are credited for their contribution. See #17719

Co-authored-by: Lms24 <[email protected]>

Author: HazAT

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 - "You miss 100 percent of the chances you don't take. — Wayne Gretzky" — Michael Scott
 
+Work in this release was contributed by @Olexandr88. Thank you for your contribution!
+
 ### Important Changes
 
 - **feat(browser): Add option to explicitly end pageload span via `reportPageLoaded()` ([#17697](https://github.com/getsentry/sentry-javascript/issues/17212))**