Adding prettybench and go-junit-report to the vendor

[krzysied]

What type of PR is this?
/kind flake

What this PR does / why we need it:
Adding github.com/cespare/prettybench and github.com/jstemmer/go-junit-report to the vendor. Testing script wills install prettybench and go-junit-report from vendor instead of downloading them.

Will fix possible flakes caused by downloading code.

Which issue(s) this PR fixes:

ref #73581 (comment)

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

/priority important-soon
/sig testing

[krzysied]

/assign @fejta

[fejta]

/lgtm

Thanks for doing this, it will make our builds more stable by go installed vendored code rather than fetching it off the network each build:

/assign @cblecker @thockin @sttts
This is for #73581, please review for approval!

[thockin]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: krzysied, thockin

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Needs approval from an approver in each of these files:

• Godeps/OWNERS [thockin]
• hack/OWNERS [thockin]
• staging/src/k8s.io/code-generator/Godeps/OWNERS [thockin]
• vendor/OWNERS [thockin]

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