Unable to install due to missing dep on aws module

[alanmcg]

go.mod requires https://github.com/aws/aws-sdk-go-v2/releases, but complains about missing awserr

go get github.com/teralytics/prometheus-ecs-discovery
build github.com/teralytics/prometheus-ecs-discovery: cannot load github.com/aws/aws-sdk-go-v2/aws/awserr: module
github.com/aws/aws-sdk-go-v2@latest found (v1.2.0), but does not contain package github.com/aws/aws-sdk-go-v2/aws/awserr

Seems like the only version with awserr in the aws release is v2.0.0-preview.5 (2018-09-27). So I am confused how to make this work!

[chicofranchico]

I just merged #64, could you try that out?