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
```
After a bunch of recent changes/rebasing our vendored dependencies got a
little out of sync w.r.t transitive dependencies through codebases that
are not themselves Go Modules yet.
Here we upgrade the AWS Go SDK to 1.12.27 and AWS provider to include terraform-providers/terraform-provider-aws#1608.
This includes the capability to use named credentials profiles from the `~/.aws/credentials` file to authenticate to the backend.
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
```