postgres: update table to use identity instead of serial (#694)

internal/dialect/dialectquery/postgres.go

@@ -8,11 +8,10 @@ var _ Querier = (*Postgres)(nil)
 
 func (p *Postgres) CreateTable(tableName string) string {
 	q := `CREATE TABLE %s (
-		id serial NOT NULL,
+		id integer PRIMARY KEY GENERATED BY DEFAULT AS IDENTITY,
 		version_id bigint NOT NULL,
 		is_applied boolean NOT NULL,
-		tstamp timestamp NULL default now(),
-		PRIMARY KEY(id)
+		tstamp timestamp NOT NULL DEFAULT now()
 	)`
 	return fmt.Sprintf(q, tableName)
 }