title: Setting deployment in bitbucket-pipeline.yml on a higher level than step
body: <p>I want to set the deployment to use for a set of steps.  All the <a href="https://support.atlassian.com/bitbucket-cloud/docs/set-up-and-monitor-bitbucket-deployments/" rel="nofollow noreferrer">documentation</a> only shows setting deployment in a bitbucket-pipelines.yml step.</p>
  <pre><code>- step:
          name: Deploy to test
          image: aneitayang/aws-cli:1.0
          deployment: testbed
          script:
            - python deploy.py test
  </code></pre>
  <p>You can't have more than 1 step indicate the same deployment.</p>
  <p>Is there a way to have multiple steps use the same deployment value?</p>
  <p>Can I set it on the pipeline level or on the branch level?</p>
  <pre><code>pipeline:
   deployment: dev
  </code></pre>
  <p>OR</p>
  <pre><code>branches:  
    feature/*:  
      deployment: dev 
  </code></pre>
  <p>OR</p>
  <p>Is it a strict 1-1 relationship of 1 step === 1 deployment?</p>