Update CHANGELOG.md

Author: lcian

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 - Attach MDC properties to logs as attributes ([#4786](https://github.com/getsentry/sentry-java/pull/4786))
   - MDC properties set using supported logging frameworks (Logback, Log4j2, java.util.Logging) are now attached to structured logs as attributes.
+  - The attribute reflected on the log is `mdc.<key>`, where `<key>` is the original key in the MDC.
   - This means that you will be able to filter/aggregate logs in the product based on these properties.
   - Only properties with keys matching the configured `contextTags` are sent as log attributes.
     - You can configure which properties are sent using `options.setContextTags` if initalizing manually, or by specifying a comma-separated list of keys with a `context-tags` entry in `sentry.properties` or `sentry.contex-tags` in `application.properties`.