fix(setup): update chunks in step 11 (#5965)

cmd/setup/11/11_add_column.sql

@@ -0,0 +1,6 @@
+BEGIN;
+-- create table with empty created_at
+ALTER TABLE eventstore.events ADD COLUMN IF NOT EXISTS created_at TIMESTAMPTZ DEFAULT NULL;
+-- set column rules
+ALTER TABLE eventstore.events ALTER COLUMN created_at SET DEFAULT clock_timestamp();
+COMMIT;