YML fix code

looking for someone who can help fix this,see error attached

image: cirrusci/flutter
pipelines:
branches:
master:
- step:
name: Build Web
script:
- flutter build web
artifacts:
- build/**

- step:
name: Deploy to Firebase
deployment: production
script:
- pipe: atlassian/firebase-deploy:1.2.0
variables:
KEY_FILE: $KEY_FILE
BUILD_DIR: $BUILD_DIR/web/