Fix gomod errors

[mikesplain]

Seems like we're running in to a bit of:

I0912 11:39:57.676] ERROR: go modules are not up to date; please run: go mod tidy
I0912 11:39:57.676] changed files:
I0912 11:39:57.677] ?? .config/
I0912 11:39:57.677] git diff:
W0912 11:39:57.716] Traceback (most recent call last):
W0912 11:39:57.716]   File "/workspace/./test-infra/jenkins/../scenarios/execute.py", line 50, in <module>
W0912 11:39:57.716]     main(ARGS.env, ARGS.cmd + ARGS.args)
W0912 11:39:57.717]   File "/workspace/./test-infra/jenkins/../scenarios/execute.py", line 41, in main
W0912 11:39:57.717]     check(*cmd)
W0912 11:39:57.717]   File "/workspace/./test-infra/jenkins/../scenarios/execute.py", line 30, in check
W0912 11:39:57.717]     subprocess.check_call(cmd)
W0912 11:39:57.717]   File "/usr/lib/python2.7/subprocess.py", line 186, in check_call
W0912 11:39:57.718]     raise CalledProcessError(retcode, cmd)
W0912 11:39:57.718] subprocess.CalledProcessError: Command '('./hack/verify-gomod',)' returned non-zero exit status 1

This is the fix of go mod tidy.

[k8s-ci-robot]

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[rifelpet]

/lgtm