Update README.md

Author: aantn

README.md

@@ -4,6 +4,6 @@ This project is a CLI tool for using [robusta](https://github.com/robusta-dev/ro
 
 * Generate Helm values for the robusta helm chart, by answering a few questions in a wizard
 * Run diagnostic to see if robusta is running properly
-* Deploy and test your own extenstions to Robusta like custom actions and playbooks.
+* Deploy and test your own extensions to Robusta like custom actions and playbooks
 
 For more infomration, checkout the [robusta installation docs](https://docs.robusta.dev/master/).