fix: expose CloudWatchMetricAlarm and CloudWatchCompositeAlarm (#926)

* fix: expose CloudWatchMetricAlarm and CloudWatchCompositeAlarm

These types are referred to by the CloudWatchAlarm type, but they previously not exported by the crate and left unused in its module.

* chore: apply rustfmt

Author: junlarsen

lambda-events/src/event/cloudwatch_alarms/mod.rs

@@ -36,12 +36,11 @@ where
 }
 
 /// `CloudWatchMetricAlarm` is the structure of an event triggered by CloudWatch metric alarms.
-#[allow(unused)]
-type CloudWatchMetricAlarm<R = CloudWatchAlarmStateReasonData> = CloudWatchAlarm<CloudWatchMetricAlarmConfiguration, R>;
+pub type CloudWatchMetricAlarm<R = CloudWatchAlarmStateReasonData> =
+    CloudWatchAlarm<CloudWatchMetricAlarmConfiguration, R>;
 
 /// `CloudWatchCompositeAlarm` is the structure of an event triggered by CloudWatch composite alarms.
-#[allow(unused)]
-type CloudWatchCompositeAlarm<R = CloudWatchAlarmStateReasonData> =
+pub type CloudWatchCompositeAlarm<R = CloudWatchAlarmStateReasonData> =
     CloudWatchAlarm<CloudWatchCompositeAlarmConfiguration, R>;
 
 #[derive(Clone, Debug, Default, Deserialize, Eq, PartialEq, Serialize)]