Notable changes:
* backend/s3: Automatic validation of `eu-north-1` region
* backend/s3: Support for `credential_process` handling in AWS configuration file
Updated via:
```
go get github.com/aws/aws-sdk-go@v1.16.4
go get github.com/terraform-providers/terraform-provider-aws@v1.52.0
go mod tidy
go mod vendor
```
There is 1 breaking change. The OpsWorks Update API no longer supports
`tenancy` as an update. So that has to be marked as ForceNew: true
```
% make testacc TEST=./builtin/providers/aws
% TESTARGS='-run=TestAccAWSOpsworksInstance'
% 2 ↵ ✹ ✭
==> Checking that code complies with gofmt requirements...
go generate $(go list ./... | grep -v /terraform/vendor/)
2017/01/02 17:11:29 Generated command/internal_plugin_list.go
TF_ACC=1 go test ./builtin/providers/aws -v
-run=TestAccAWSOpsworksInstance -timeout 120m
=== RUN TestAccAWSOpsworksInstance
--- PASS: TestAccAWSOpsworksInstance (99.89s)
PASS
ok github.com/hashicorp/terraform/builtin/providers/aws99.911s
```