Add target annotation to expiry annotation. (#1193)

It should have already had this as it was being used as an annotation
in AirportRepository.ComposedMetaAnnotation.
I believe a recent update to intellij now flags it as an error in the IDE.

Closes #1192.

src/main/java/org/springframework/data/couchbase/core/mapping/Expiry.java

@@ -33,7 +33,7 @@ import org.springframework.data.annotation.Persistent;
 @Persistent
 @Inherited
 @Retention(RetentionPolicy.RUNTIME)
-@Target({ ElementType.TYPE })
+@Target({ ElementType.TYPE, ElementType.ANNOTATION_TYPE })
 public @interface Expiry {
 
 	/**