Merge pull request sorintlab#711 from sgotti/readme_use_agola_run_badge

readme: use agola run badge

Author: sgotti

README.md

@@ -1,6 +1,6 @@
 # stolon - PostgreSQL cloud native High Availability
 
-[![Build Status](https://semaphoreci.com/api/v1/projects/fb01aecd-c3d5-407b-a157-7d5365e9e4b6/565617/badge.svg)](https://semaphoreci.com/sorintlab/stolon)
+[![Build Status](https://run.agola.io/api/v1alpha/badges/org%2Fstolon%2Fstolon?branch=master)](https://run.agola.io/org/stolon/projects/stolon.proj)
 [![Join the chat at https://gitter.im/sorintlab/stolon](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/sorintlab/stolon?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 [![Go Report Card](https://goreportcard.com/badge/github.com/sorintlab/stolon)](https://goreportcard.com/report/github.com/sorintlab/stolon)
 [![Downloads](https://img.shields.io/github/downloads/sorintlab/stolon/latest/total.svg)](https://github.com/sorintlab/stolon/releases)