Add GitLab pipeline status. (#29)

Author: BorjaOuterelo

README.md

@@ -1,5 +1,7 @@
 # micro-ROS web site
 
+[![pipeline status](https://gitlab.com/micro-ROS/ci-support/micro-ROS-github-io/badges/master/pipeline.svg)](https://gitlab.com/micro-ROS/ci-support/micro-ROS-github-io/commits/master)
+
 This is the source for the micro-ROS website, available
 at [https://micro-ros.github.io/](https://micro-ros.github.io/)