Jenkinsfile: send mail to committer on failing build

Jenkinsfile

@@ -50,5 +50,10 @@ pipeline {
         always {
             sh 'rm -rf venv'
         }
+        changed {
+            emailext body: "Check console output at ${env.BUILD_URL}",
+                recipientProviders: [[$class: 'DevelopersRecipientProvider'], [$class: 'RequesterRecipientProvider']],
+                subject: "${buildStatus}: Job '${env.JOB_NAME} [${env.BUILD_NUMBER}]'"
+        }
     }
 }