try to fix the library build

Author: rbri

src/jenkins/library-tests

@@ -18,11 +18,13 @@ pipeline {
   }
   post {
     always {
-      junit allowEmptyResults: true, testResults: 'target/surefire-reports/**/*.xml'
-      recordIssues enabledForFailure: true, sourceCodeEncoding: 'UTF-8', tools: [java()]
-      step([$class: 'Mailer',
-        notifyEveryUnstableBuild: true,
-        recipients: "rbri@rbri.de"])
+      node('') {
+        junit allowEmptyResults: true, testResults: 'target/surefire-reports/**/*.xml'
+        recordIssues enabledForFailure: true, sourceCodeEncoding: 'UTF-8', tools: [java()]
+        step([$class: 'Mailer',
+          notifyEveryUnstableBuild: true,
+          recipients: "rbri@rbri.de"])
+      }
     }
   }
 }