Add changelog message

Author: tobias-wilfert

CHANGELOG.md

@@ -7,7 +7,8 @@
 - feat(log): support combined LogFilters and RecordMappings ([#914](https://github.com/getsentry/sentry-rust/pull/914)) by @lcian
   - Breaking change: `sentry::integrations::log::LogFilter` has been changed to a `bitflags` struct.
   - It's now possible to map a `log` record to multiple items in Sentry by combining multiple log filters in the filter, e.g. `log::Level::ERROR => LogFilter::Event | LogFilter::Log`.
-  - If using a custom `mapper` instead, it's possible to return a `Vec<sentry::integrations::log::RecordMapping>` to map a `log` record to multiple items in Sentry. 
+  - If using a custom `mapper` instead, it's possible to return a `Vec<sentry::integrations::log::RecordMapping>` to map a `log` record to multiple items in Sentry.
+  - Add custom variant to `AttachmentType` that holds an arbitrary String. ([#916](https://github.com/getsentry/sentry-rust/pull/916))
 
 ### Behavioral changes