Class name console string literal added

vars/printBuildinfo.groovy

@@ -12,6 +12,6 @@ def call(body) {
     if (env.param1 == 'One default') {
         echo "Param1 is default"
     }
-    println "Class: $this.class.name"
+    println "Class: ${this.class.name}"
     return this
 }