aws:download content document to support tokenInfo from cross account ssm parameter

[spongenee]

I would like to run command from multiple accounts within the organization. Instead of creating a github token parameter in each account, I would like to only create one in the management account and share it across the organization.

Right now, secure-string-token in "tokenInfo":"{{ssm-secure:secure-string-token}}" is the name of parameter within the same account, I would like it to should support arn as well so that we can get the parameter as a shared resource from another account.

[spongenee]

https://github.com/aws/amazon-ssm-agent/blob/da9a3363e1d1a04cc69e7aba71bd33844a376eac/agent/ssm/ssmparameterresolver/ssm.go

This will be the file to modify