Update README.md

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README.md

 * [PHPSecLib](http://phpseclib.sourceforge.net/) - A pure PHP secure communications library.
 * [random_compat](https://github.com/paragonie/random_compat) - PHP 5.x support for `random_bytes()` and `random_int()`
 * [RandomLib](https://github.com/ircmaxell/RandomLib) - A library for generating random numbers and strings.
-* [SensioLabs Security Check](https://security.sensiolabs.org/) - A web tool to check your Composer dependencies for security advisories.
+* [Symfony Security Monitoring](https://security.symfony.com/) - A web tool to check your Composer dependencies for security advisories, previously known as "SensioLabs Security Check".
 * [TCrypto](https://github.com/timoh6/TCrypto) - A simple encrypted key-value storage library.
 * [VAddy](https://vaddy.net/) - A continuous security testing platform for web applications.
 * [Zed](https://www.owasp.org/index.php/OWASP_Zed_Attack_Proxy_Project) - An integrated penetration testing tool for web applications.