postgresql: Disable validation of connectionString field (#6397)

A bug concerning the validation of connectionString is found,
however there is no solution to fix it for now, postgresql API
doesn't help to do that hence disabling validation of that field.

pkg/event/target/postgresql.go

@@ -62,7 +62,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/lib/pq" // Register postgres driver
 	"github.com/minio/minio/pkg/event"
 	xnet "github.com/minio/minio/pkg/net"
 )
@@ -106,9 +105,8 @@ func (p PostgreSQLArgs) Validate() error {
 	}
 
 	if p.ConnectionString != "" {
-		if _, err := pq.ParseURL(p.ConnectionString); err != nil {
-			return err
-		}
+		// No pq API doesn't help to validate connection string
+		// prior connection, so no validation for now.
 	} else {
 		// Some fields need to be specified when ConnectionString is unspecified
 		if p.Port == "" {