vendor: update all dependencies

* Update all dependencies
  * Remove all `[[constraint]]` from Gopkg.toml
  * Add in the minimum number of `[[override]]` to build
  * Remove go get of github.com/inconshreveable/mousetrap as it is vendored
  * Update docs with new policy on constraints

vendor/github.com/aws/aws-sdk-go/service/clouddirectory/clouddirectoryiface/interface.go

@@ -172,6 +172,10 @@ type CloudDirectoryAPI interface {
 	GetFacetWithContext(aws.Context, *clouddirectory.GetFacetInput, ...request.Option) (*clouddirectory.GetFacetOutput, error)
 	GetFacetRequest(*clouddirectory.GetFacetInput) (*request.Request, *clouddirectory.GetFacetOutput)
 
+	GetObjectAttributes(*clouddirectory.GetObjectAttributesInput) (*clouddirectory.GetObjectAttributesOutput, error)
+	GetObjectAttributesWithContext(aws.Context, *clouddirectory.GetObjectAttributesInput, ...request.Option) (*clouddirectory.GetObjectAttributesOutput, error)
+	GetObjectAttributesRequest(*clouddirectory.GetObjectAttributesInput) (*request.Request, *clouddirectory.GetObjectAttributesOutput)
+
 	GetObjectInformation(*clouddirectory.GetObjectInformationInput) (*clouddirectory.GetObjectInformationOutput, error)
 	GetObjectInformationWithContext(aws.Context, *clouddirectory.GetObjectInformationInput, ...request.Option) (*clouddirectory.GetObjectInformationOutput, error)
 	GetObjectInformationRequest(*clouddirectory.GetObjectInformationInput) (*request.Request, *clouddirectory.GetObjectInformationOutput)

vendor/github.com/aws/aws-sdk-go/service/clouddirectory/errors.go

@@ -45,7 +45,7 @@ const (
 	// ErrCodeDirectoryNotEnabledException for service response error code
 	// "DirectoryNotEnabledException".
 	//
-	// An operation can only operate on a directory that is not enabled.
+	// Operations are only permitted on enabled directories.
 	ErrCodeDirectoryNotEnabledException = "DirectoryNotEnabledException"
 
 	// ErrCodeFacetAlreadyExistsException for service response error code

vendor/github.com/aws/aws-sdk-go/service/clouddirectory/service.go

@@ -45,14 +45,14 @@ const (
 //     svc := clouddirectory.New(mySession, aws.NewConfig().WithRegion("us-west-2"))
 func New(p client.ConfigProvider, cfgs ...*aws.Config) *CloudDirectory {
 	c := p.ClientConfig(EndpointsID, cfgs...)
+	if c.SigningNameDerived || len(c.SigningName) == 0 {
+		c.SigningName = "clouddirectory"
+	}
 	return newClient(*c.Config, c.Handlers, c.Endpoint, c.SigningRegion, c.SigningName)
 }
 
 // newClient creates, initializes and returns a new service client instance.
 func newClient(cfg aws.Config, handlers request.Handlers, endpoint, signingRegion, signingName string) *CloudDirectory {
-	if len(signingName) == 0 {
-		signingName = "clouddirectory"
-	}
 	svc := &CloudDirectory{
 		Client: client.New(
 			cfg,