fix(random): add missing import for random crate update

Author: Akinator31

crates/rustmail/src/db/operations/api_keys.rs

@@ -1,7 +1,7 @@
 use crate::db::repr::{ApiKey, Permission};
 use chrono::Utc;
 use hex;
-use rand::Rng;
+use rand::RngExt;
 use sha2::{Digest, Sha256};
 use sqlx::{Row, SqlitePool};