ref: Add external contributor to CHANGELOG.md (#13749)

This PR adds the external contributor to the CHANGELOG.md file, so that
they are credited for their contribution. See #13711

Co-authored-by: lforst <8118419+lforst@users.noreply.github.com>

Author: github-actions[bot]

CHANGELOG.md

@@ -12,6 +12,8 @@
 - Moved description of `browser` spans into the operation, e.g. `browser - cache` -> `browser.cache` and set the URL as
   the description
 
+Work in this release was contributed by @Zen-cronic. Thank you for your contribution!
+
 ## 8.31.0
 
 ### Important Changes