fix bulk insert in csv template

snippets/migration/csv.template.js

@@ -42,8 +42,8 @@ async function up (knex) {
   const data = await get_csv ();
   await Promise.all (
     data.map (
-      (table) => knex (table.name)
-        .insert (table.data)
+      // eslint-disable-next-line no-magic-numbers
+      (table) => knex.bulkInsert (table.name, table.data, 64)
     )
   );
 }