Updated Security section (#9914)

Added a link to Professor Messer’s SY0-601 CompTIA Security+ Course

courses/free-courses-en.md

@@ -1441,6 +1441,7 @@
 * [Learn Ethical Haacking From Scratch](https://www.udemy.com/course/learn-ethical-haacking-from-scratch) - Uzma Aslam (Udemy)
 * [Linux for Hackers and Pentesters](https://www.udemy.com/course/linux-for-hackers-and-pentesters) - Rajneesh Gupta (Udemy)
 * [Modern Binary Exploitation](https://github.com/RPISEC/MBE) - RPISEC
+* [Professor Messer’s SY0-601 CompTIA Security+ Course](https://www.professormesser.com/security-plus/sy0-601/sy0-601-video/sy0-601-comptia-security-plus-course/) - Professor Messer
 * [Stanford Cryptography I](https://www.coursera.org/course/crypto) - Dan Boneh
 * [Stanford Cryptography II](https://www.coursera.org/course/crypto2) - Dan Boneh
 * [Start Ethical Hacking with Parrot Security OS (Alt. to Kali)](https://www.udemy.com/course/ethical-hacking-with-parrot-security-os) - Seyed Farshid Miri (Udemy)