Add ip validation

Author: Pavlusha311245

src/Config/Upstream.php

@@ -4,6 +4,7 @@
 
 use OutOfRangeException;
 use UnitPhpSdk\Contracts\UpstreamInterface;
+use UnitPhpSdk\Exceptions\UnitException;
 use UnitPhpSdk\Traits\HasListeners;
 
 /**
@@ -46,13 +47,18 @@ private function setServers(array $servers): void
      * @param string $ip
      * @param int $weight
      * @return void
+     * @throws UnitException
      */
     public function setServer(string $ip, int $weight = 1): void
     {
         if ($weight < 0 || $weight > 1000000) {
             throw new OutOfRangeException('Weight should be between 0 and 1000000');
         }
 
+        if (!filter_var($ip, FILTER_VALIDATE_IP)) {
+            throw new UnitException("{$ip} isn't a valid IP address");
+        }
+
         $this->_servers[$ip] = [
             'weight' => $weight
         ];