Add the ability to specify which region to extract an ssm param for in the parameter files

[thomasmcgannon]

Currently you can use the resolve: keyword in the params .json files to resolve parameters that are stored in the SSM Parameter Store, however this only allows you to retrieve the parameter form the main deployment account region.

{
    "Parameters" : {
        "SomeParam":"resolve:/path/to/key"
    }
}

Having a way to specify or override the region (like below for example), would help with multi-region deployments.

{
    "Parameters" : {
        "SomeParam":"resolve:/**region**/path/to/key"
    }
}

[bundyfx]

PR #26 has been merged into master

If you wish to resolve parameters in the default deployment region you can use resolve:/path/to/param or if you wish to resolve from a different region within the deployment account you can pass resolve:eu-west-1:/path/to/param (eu-west-1 being the example)

[tmaior]

hello, can help?
not working in:
AWS::ECS::TaskDefinition

Environment:
- Name: SLACK_WEBHOOK
Value: !Sub "{{resolve:us-east-1:/GENERAL/SECURITY_SLACK_WEBHOOK:1}}"