ci: fix syntax

Jenkinsfile

@@ -2,36 +2,39 @@ pipeline {
     agent any
 
     options {
-        buildDiscarder {
+        buildDiscarder (
             logRotator(numToKeepStr: '5')
-        }
+        )
     }
 
-    stage("Build") {
-        agent {
-            label "flutter"
-        }
+    stages {
+        stage("Build") {
+            agent {
+                label "flutter"
+            }
 
-        steps {
-            sh '''
-            #!/bin/bash
+            steps {
+                sh '''
+                #!/bin/bash
 
-            flutter pub get
+                flutter pub get
 
-            flutter build web
+                flutter build web
 
-            cd build/web
-            tar -cvf ../../web.tgz .
+                cd build/web
+                tar -cvf ../../web.tgz .
 
-            '''
-        }
+                '''
+            }
 
-        post {
-            always {
-                archiveArtifacts artifacts: "web.tgz"
+            post {
+                always {
+                    archiveArtifacts artifacts: "web.tgz"
 
-                cleanWs()
+                    cleanWs()
+                }
             }
         }
     }
+    
 }