fixed wrong command

Jenkinsfile

@@ -21,7 +21,7 @@ pipeline {
                     sh 'npm config set registry https://registry.npmmirror.com'                        
                     sh 'npm install'                        
                     sh 'npm run build' 
-                    sh 'la -al'                       
+                    sh 'ls -al'                       
                 }                
             }            
         }