Change timestamp data type. (#4355)

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

src/db/schemas/mysql/schema.rs

@@ -160,7 +160,7 @@ table! {
         atype -> Integer,
         enabled -> Bool,
         data -> Text,
-        last_used -> Integer,
+        last_used -> BigInt,
     }
 }