Bump "safe" dependencies

[vdemeester]

This bump some "safe" dependencies atomically (as 1 update per commit). By "safe" dependency, I means it tried to update dependency that are not constrained, nor overridden, and that do not track master.

This has been done using sec, which mens:

• It tried to update the dependency
• Ran tests to validate it doesn't break (at least the build) (go test ./... or go test ./pkg/..., …).
• Commit if the test command was successful.

sec is really experimental, but my end-goal is to have some kind of bot that could update those safe deps for us 👼.
Also, this never update to latest either (if latest is the latest release, even if it's a major version bump). It's only updating minor or fixes versions.

Related PR "upstream" knative/pkg#200

/assign @mattmoor

[vdemeester]

/test pull-knative-serving-go-coverage

[mattmoor]

/lgtm
/approve

[knative-prow-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mattmoor, vdemeester

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