Automatic merge from submit-queue
vendor: Update elazarl/goproxy to fix e2e test with go1.8
**What this PR does / why we need it**:
This updates the dependency `github.com/elazarl/goproxy` to include this fix c4fc26588b which makes kubernetes e2e tests build with go1.8. It was crashing before as described in https://github.com/elazarl/goproxy/issues/188#issuecomment-281092250 and #38228
**Which issue this PR fixes**
This is part of the fix for #38228
**Special notes for your reviewer**:
**Release note**:
```release-note
```