Change build selector - 6.2 training

Jenkinsfile_training

@@ -1,10 +1,15 @@
 pipeline {
     agent {dockerfile true}	
-	
+	parameters {
+		buildSelector(
+					defaultSelector: lastSuccessful(),
+					description: 'Which build to use for copying artifacts',
+					name: 'BUILD_SELECTOR')
+	}
     stages {
 		stage('copyArtifacts') {
             steps {
-                copyArtifacts fingerprintArtifacts: true, projectName: 's434684-create-dataset', selector: latestSuccessful(true)
+                copyArtifacts fingerprintArtifacts: true, projectName: 's434684-create-dataset', selector: buildParameter('BUILD_SELECTOR')
             }
         }
 		stage('Sh script') {