feat: fix bug in Postgres dialect where if a table already exists then it would give error (Invalid query) (#58)

Author: vishal-bihani

go.mod

@@ -3,8 +3,9 @@ module github.com/casbin/xorm-adapter/v3
 go 1.12
 
 require (
+	github.com/PuerkitoBio/goquery v1.5.1 // indirect
 	github.com/casbin/casbin/v2 v2.28.3
-	github.com/go-sql-driver/mysql v1.5.0
-	github.com/lib/pq v1.8.0
-	xorm.io/xorm v1.0.3
+	github.com/go-sql-driver/mysql v1.6.0
+	github.com/lib/pq v1.10.2
+	xorm.io/xorm v1.3.2
 )