Automatic merge from submit-queue (batch tested with PRs 55092, 55348, 55095, 55277, 55352). 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>.
proxy: cleanup old build file
this is cruft from when we moved the apigroup.
```release-note
NONE
```