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 https://github.com/elazarl/goproxy/commit/c4fc26588b6ef8af07a191fcb6476387bdd46711 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
```