Update training overview

Added Pluralsight getting started course

Author: jonasmellquist

content/en/docs/tutorials/online-training/overview.md

@@ -15,6 +15,8 @@ Here are some of the sites that offer online training for Kubernetes:
 
 * [Introduction to Kubernetes (edX)](https://www.edx.org/course/introduction-kubernetes-linuxfoundationx-lfs158x)
 
+* [Getting Started with Kubernetes (Pluralsight)](https://www.pluralsight.com/courses/getting-started-kubernetes)
+
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