Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Add liggitt to hack approvers

* Authored ~60 commits involving this folder
* Already an approver on things with components in hack (CLI tests, apiserver changes requiring local-up-cluster changes, fixtures and testdata, etc)

```release-note
NONE
```