Change timestamp data type. (#4355)

Co-authored-by: Daniel García <dani-garcia@users.noreply.github.com>

src/db/models/two_factor.rs

@@ -12,7 +12,7 @@ db_object! {
         pub atype: i32,
         pub enabled: bool,
         pub data: String,
-        pub last_used: i32,
+        pub last_used: i64,
     }
 }