Fixed - pkg_resources.DistributionNotFound: The 'zappa' distribution was not found and is required by the application
when deploying or updating

PR - When granting permissions to invoke a lambda for an event source such as s3 object created, specify the SourceAccount to restrict access to the lambda function to strictly that account. This is a minor change to prevent public access to a lambda function.

Troposphere Attribute Error - method "add_description" in zappa/core.py line 2417 doesn't exists in the latest troposphere library, method "set_description" takes it's place. This change allows for "zappa deploy" and "zappa update" without errors.