fix issue walidshaari#43 (walidshaari#44)

- add back udemy CKS course with discount
- fix issue walidshaari#43

README.md

@@ -270,7 +270,8 @@ Offical exam objectives you review and understand in order to pass the test.
 ### Containers and Kubernetes Security Training
 
 1. [Killer.sh CKS practice exam](https://killer.sh/cks) - use code **walidshaari** for **20%** discount.
-1. [Linux Foundation Kubernetes Security essentials LFS 260](https://training.linuxfoundation.org/training/kubernetes-security-essentials-lfs260/) -  available January 8, 2021.
+1. UDEMY Kim Wüstkamp's [Kubernetes CKS 2021 Complete Course with killer.sh Simulator **(discounted price)**](https://killer.sh/r?d=cks-course)
+1. [Linux Foundation Kubernetes Security essentials LFS 260](https://training.linuxfoundation.org/training/kubernetes-security-essentials-lfs260/)
 1. [Linux Academy/ACloudGuru Kubernetes security](https://acloud.guru/learn/7d2c29e7-cdb2-4f44-8744-06332f47040e)
 1. Zeal Vora's Udemy [ Certified Kubernetes Security Specialist 2021 ](https://www.udemy.com/course/certified-kubernetes-security-specialist-certification/?referralCode=F38A7E4C09BFEC7E3C58) - Link includes a discount till 28th January 2021
 1. [Cloud native security defending containers and kubernetes](https://www.sans.org/event/stay-sharp-blue-team-ops-and-cloud-dec-2020/course/cloud-native-security-defending-containers-kubernetes)
@@ -285,4 +286,4 @@ Offical exam objectives you review and understand in order to pass the test.
 1. [Kim's CKS Challenge series](https://github.com/killer-sh/cks-challenge-series) - also posted on medium @ https://wuestkamp.medium.com/
 1. [Abdennour](https://github.com/abdennour/certified-kubernetes-security-specialist)
 1. [Ibrahim Jelliti](https://github.com/ijelliti/CKSS-Certified-Kubernetes-Security-Specialist)
-1. [Viktor Vedmich](https://github.com/vedmichv/CKS-Certified-Kubernetes-Security-Specialist)
+1. [Viktor Vedmich](https://github.com/vedmichv/CKS-Certified-Kubernetes-Security-Specialist)