title: How to add environment variables in template.yaml in a secured way?
body: <p>When creating Lambda function through the SAM CLI using <code>template.yaml</code>, I have to pass few environment variables, and they shouldn't be exposed on GitHub. Is there any way I can refer the environment variables in <code>template.yaml</code> through the <code>.env</code> file?</p>
  <p>I didnt find any sources for the same.</p>
  <p>Sample code snippet from template.yaml:</p>
  <pre><code>Properties:
    CodeUri: student /
    FunctionName: list
    Handler: index.listHandler
    Runtime: nodejs14.x
    Environment: 
      Variables:
        MONGODB_URI: mongodb://username:pwd
  </code></pre>