Cannot generate IAM Policy for dynamodb:scan

[ebisbe]

This is a Feature Proposal

Description

For bug reports:

• What went wrong?

Cannot generate IAM policy statement for Task state { Type: 'Task',
  Next: 'Map',
  Parameters:
   { TableName: { Ref: 'flickrTokens' },
     FilterExpression: '#isSubscribed = :isNotSubscribed',
     ExpressionAttributeNames: { '#isSubscribed': 'isSubscribed' },
     ExpressionAttributeValues: { ':isNotSubscribed': { Bool: false } },
     'ExclusiveStartKey.$': '$.LastEvaluatedKey' },
  Resource: 'arn:aws:states:::aws-sdk:dynamodb:scan' }

• What did you expect should have happened?
  Generate the proper IAM role

For feature proposals:
Add the line to generate the iam role for scan. Not sure why it has not been added. I need it to scan a users table.

I can do the PR myself