feat(migrations): add pg_search extension update migration files

- Create up migration to update pg_search extension to the latest version.
- Create down migration noting that the update cannot be rolled back.

Author: lyingbug

migrations/versioned/000011_pg_search_update.down.sql

@@ -0,0 +1,2 @@
+-- Migration 000011 Down: pg_search extension update cannot be rolled back
+-- No-op: ALTER EXTENSION UPDATE has no reverse operation

migrations/versioned/000011_pg_search_update.up.sql

@@ -0,0 +1,4 @@
+-- Migration 000011: Update pg_search extension to latest version
+-- Equivalent to: psql -c 'ALTER EXTENSION pg_search UPDATE;'
+
+ALTER EXTENSION pg_search UPDATE;