docs: Add external contributors to 8.8.0 changelog note (#12413)

Forgot to shoutout @dohooo, @mohd-akram and @ykzts for their help fixing
bugs with the SDK this release - will also update the main release
notes!

Author: AbhiPrasad

CHANGELOG.md

@@ -48,6 +48,8 @@ If you are still encountering issues with OpenTelemetry instrumentation and ESM,
 - ref(browser): Ensure idle span ending is consistent (#12310)
 - ref(profiling): unref timer (#12340)
 
+Work in this release contributed by @dohooo, @mohd-akram, and @ykzts. Thank you for your contributions!
+
 ## 8.7.0
 
 ### Important Changes