TaskDeletion struct has incorrect type for field deleted_tasks

[coinmoles]

Description

When trying to call perform get_task() for a deletion task, I get an error:

Error parsing response JSON: invalid type: null, expected usize.

After getting the response object by calling the api manually and comparing it to the structs, I found out that deletedTasks was null in my response object, while the deleted_tasks field in struct TaskDeletion is usize and not Option<usize>

meilisearch-rust/src/tasks.rs

Lines 115 to 121 in 90a153c

	#[derive(Debug, Clone, Deserialize)]
	#[serde(rename_all = "camelCase")]
	pub struct TaskDeletion {
	pub matched_tasks: usize,
	pub deleted_tasks: usize,
	pub original_filter: String,
	}

According to the API documentation, the deleted_tasks can be null when the task is enqueued or processing.