Make version optional and remove 'latest'

[leecrossley]

We want to be able to make the package name lamdba_thing.zip

[Tim-B]

Hi Lee, thanks for the pull request!

My only concern is that by removing latest from the name it will change the naming convention for existing users who have include_time = false and don't have include_version set.

I made an option to have a static artifact name for users who have a deployment script or something that runs afterwards.

You can find an example use case of that here: https://aws.amazon.com/blogs/compute/continuous-integration-deployment-for-aws-lambda-functions-with-jenkins-and-grunt-part-2/

Set the Artifact Location to dist/create-thumbs-lambda_0-0-1_latest.zip as this is where Grunt generates the Lambda function bundle

Your pull request will help those users (seeing as the version name won't be dynamic), but I'd prefer the artifact name remained identical for existing users who don't have the include_version option set.

[Tim-B]

An include_version option has been added in the latest version which should resolve this issue.