Add links to sketch compilation actions

Author: per1234

README.md

@@ -2,9 +2,10 @@
 
 [![Compile Sketch status](https://github.com/arduino/arduino-cli-example/actions/workflows/compile-sketch.yml/badge.svg)](https://github.com/arduino/arduino-cli-example/actions/workflows/compile-sketch.yml)
 
-This repository is the companion of an article on Arduino's blog about tools for continuous integration testing of Arduino sketches with GitHub Actions.
+This repository is the companion of [an article on Arduino's blog](https://blog.arduino.cc/2021/04/09/test-your-arduino-projects-with-github-actions/) about tools for continuous integration testing of Arduino sketches with GitHub Actions.
 
 It only serves as a basic demonstration of the [`arduino/compile-sketches` GitHub Actions action](https://github.com/arduino/compile-sketches).
 
+- See the blog post [here](https://blog.arduino.cc/2021/04/09/test-your-arduino-projects-with-github-actions/)
 - See the workflow [here](https://github.com/arduino/arduino-cli-example/blob/compile-sketches-demo/.github/workflows/compile-sketch.yml)
 - See the workflow runs [here](https://github.com/arduino/arduino-cli-example/actions/workflows/compile-sketch.yml)