如何为terraform更新https://github.com/hashicorp/terraform.git的供应商文件夹

Hi i am following steps given for hashicorp/terraform and performed below activity

# Get latest master branch's dependencies staged in local $GOPATH
git checkout master
git pull
godep restore -v

# Make your way to the dependency in question and checkout the target ref
pushd $GOPATH/src/github.com/some/dependency
git checkout [latest]

# Head back to Terraform on a feature branch and update the dependncy to the
# version currently in your $GOPATH
popd
git checkout my-feature-branch
godep update github.com/...

after this i can see my Godep.json file has been updated however i dont see changes in the vendor folder . it still points to old. Well i am looking emr support from vendor for that i am updating go-aws-sdk which is available with the latest go-aws-sdk. when i called go update github.com/... it has modified the godep.json but not vendor folder . Could somebody please let me know the reason. Thanks

You have to do a godep restore -v again. update only updates the dependency in the Godep.json file.