Support IAM role for S3

[Gauravshah]

Expected Behaviour

we should be able to use default IAM role instead of having hardcoded keys

Actual Behaviour

we send in aws_keys via code

commands that can be used

boto3.client( 's3') should automatically pick up IAM

[yaojiach]

I think if you just do:

connect_to_s3(aws_access_key_id=None, aws_secret_access_key=None, bucket='bucket')

boto3 will default fall back to .aws/credentials first and then environment variables

[yaojiach]

Closing this issue as it can be done by passing None to the arguments.

[Gauravshah]

Thanks will give it a shot