`aws-inventory ecs` fails because it does not pass parameter `Services` to the AWS SDK

Here's the stack-trace:

```
C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-sdk-core-3.25.0/lib/seahorse/client/plugins/raise_response_errors.rb:15:in `call': Services cannot be empty. (Aws::ECS::Errors::InvalidParameterException)
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-sdk-core-3.25.0/lib/aws-sdk-core/plugins/jsonvalue_converter.rb:20:in `call'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-sdk-core-3.25.0/lib/aws-sdk-core/plugins/idempotency_token.rb:17:in `call'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-sdk-core-3.25.0/lib/aws-sdk-core/plugins/param_converter.rb:24:in `call'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-sdk-core-3.25.0/lib/aws-sdk-core/plugins/response_paging.rb:10:in `call'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-sdk-core-3.25.0/lib/seahorse/client/plugins/response_target.rb:23:in `call'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-sdk-core-3.25.0/lib/seahorse/client/request.rb:70:in `send_request'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-sdk-ecs-1.17.0/lib/aws-sdk-ecs/client.rb:1663:in `describe_services'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-inventory-0.4.3/lib/aws_inventory/ecs/service.rb:25:in `block in ecs_services'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-inventory-0.4.3/lib/aws_inventory/ecs/service.rb:23:in `map'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-inventory-0.4.3/lib/aws_inventory/ecs/service.rb:23:in `ecs_services'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-inventory-0.4.3/lib/aws_inventory/ecs/service.rb:7:in `data'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-inventory-0.4.3/lib/aws_inventory/base.rb:16:in `report'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-inventory-0.4.3/lib/aws_inventory/ecs.rb:7:in `report'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-inventory-0.4.3/lib/aws_inventory/cli.rb:65:in `ecs'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/thor-0.20.0/lib/thor/command.rb:27:in `run'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/thor-0.20.0/lib/thor/invocation.rb:126:in `invoke_command'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/thor-0.20.0/lib/thor.rb:387:in `dispatch'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-inventory-0.4.3/lib/aws_inventory/command.rb:21:in `dispatch'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/thor-0.20.0/lib/thor/base.rb:466:in `start'
from C:/Ruby24-x64/lib/ruby/gems/2.4.0/gems/aws-inventory-0.4.3/exe/aws-inventory:14:in `'
from C:/Ruby24-x64/bin/aws-inventory:23:in `load'
from C:/Ruby24-x64/bin/aws-inventory:23:in `'
```