Add support for new Distributed Map in Step Functions Definition

[harazdovskiy]

Is your feature request related to a problem? Please describe.
Wide known serverless-step-functions module depends on asl in this place. As @brycenrogers mentioned here

Note: this does not currently work with validate: true as asl-validator does not yet support this behavior.

I've recently faced a limitation in step function, found out it can be fixed with new functionality however syntax validator (asl-validator) does not support it(

We kindly ask to extend the asl-validator with support of new DISTRIBUTED Map options

Describe the solution you'd like
I guess this file should be updated with new properties that Map supports.
Then I will initiate the serverless-step-functions module to update asl-validate -> now we can deploy step functions with fresh AWS functionality altogether)

Describe alternatives you've considered
Don't think we can avoid updating the asl-validator with new AWS functionality

Additional context
https://docs.aws.amazon.com/step-functions/latest/dg/concepts-inline-vs-distributed-map.html

[ChristopheBougere]

@harazdovskiy #116 has been released in v3.1.0, could you give it a try?

[harazdovskiy]

Big thanks to you guys @massfords, @ChristopheBougere! Tested new asl-validator with latest changes of sls-step function. All tests passed

Before:

With new version