Hi Everyone! While working on some dependency improvements to pulsar-client-go, I noticed that the oauth2 sub-directory is defined as a go sub-module instead of just a normal sub-directory. This just means it has its own go.mod and go.sum, and it's dependencies are separately managed from the main library. Sub-modules like this are not that common in golang projects since they make it a bit more difficult to keep dependencies up to date. The main use case is if the sub directory has its own release cycle separate from the main directory [1], but that's not the case here. In fact, there is currently a dependency conflict in that the main module is depending on a newer version of 'golang.org/x/oauth2' than the oauth2 sub-module, and an upgrade currently causes test failures in the oauth2 sub-module.
I didn't see any specific reason for adding the go sub-module in the original PR [2], so I'm not sure if there is any reason to keep it. I created a PR to remove the sub-module [3], bring the 'golang.org/x/oauth2' dependency in sync, and update the tests to work with the newer version. Please discuss if you have any concerns about this change, thanks! [1] https://stackoverflow.com/a/64667433/1637116 [2] https://github.com/apache/pulsar-client-go/pull/313 [3] https://github.com/apache/pulsar-client-go/pull/802
