Make user nullable

Author: Volodymyr Chernyshov

danger-kotlin-library/src/main/kotlin/systems/danger/kotlin/models/bitbucket/BitBucketCloud.kt

@@ -32,7 +32,7 @@ data class BitBucketCloud(
         @SerialName("updated_on")
         val updatedOn: Instant,
         val deleted: Boolean,
-        val user: User,
+        val user: User? = null,
     )
 
     @Serializable