title: In GCP, through Cloudbuild how can I ensure that only those steps get triggered for which changes have happened in file
body: <p>My issue is that, given the below yaml file, if I'm making changes for example in any file of "dir: process/cbd-bu-data", Cloud Build runs all the steps serially when triggered. This leads to wastage of time.</p>
  
  <p>I want that only that step runs in cloudbuild for which the changes have been made in file of that directory. What should I do to achieve this?</p>
  
  <p>Here's my <code>cloudbuild.yaml</code> file:</p>
  
  <pre><code>steps: 
    - args: 
        - beta
        - functions
        - deploy
        - "--runtime=python37"
        - "--trigger-http"
        - "--entry-point=process_cbd_group_data"
        - process_cbd_group_data
        - "--region=us-central1"
      dir: process/cbd-group-data
      name: gcr.io/cloud-builders/gcloud
    - args: 
        - beta
        - functions
        - deploy
        - "--runtime=python37"
        - "--trigger-http"
        - "--entry-point=process_cbd_bu_data"
        - process_cbd_bu_data
        - "--region=us-central1"
      dir: process/cbd-bu-data
      name: gcr.io/cloud-builders/gcloud
    - args: 
        - beta
        - functions
        - deploy
        - "--runtime=python37"
        - "--trigger-http"
        - "--entry-point=process_cbd_structure_data"
        - process_cbd_structure_data
        - "--region=us-central1"
      dir: process/cbd-structure-data
      name: gcr.io/cloud-builders/gcloud  
  </code></pre>