Drop VPA vendor directory in favor of Go modules

[fmuyassarov]

What type of PR is this?

/kind cleanup
/kind deprecation

What this PR does / why we need it:

Drop vertical-pod-autoscaler vendor directory in favor of Go modules. We're started this process
from cluster-autoscaler in #6572.

Which issue(s) this PR fixes:

Fixes #4878

Special notes for your reviewer:

After this I will file one more PR for dropping vendor-directory in addon-resizer too.

Does this PR introduce a user-facing change?

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: fmuyassarov
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[fmuyassarov]

/cc @x13n @Shubham82

[k8s-ci-robot]

@fmuyassarov: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-kubernetes-e2e-autoscaling-vpa-full	6b18596	link	false	/test pull-kubernetes-e2e-autoscaling-vpa-full

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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[x13n]

#4878 was specifically about CA. We need to check with VPA owners if this is also a desired change here.

/assign kwiesmueller

[kwiesmueller]

Personally I prefer having a vendor directory as it makes it way easier to review the actual code being patched in PRs (which is getting more and more essential in a time where supply chain attacks are on the rise).
We still need CI that checks that the checked-in vendor files match the mod file to avoid malicious vendor check-ins, but the review ergonomics become way better with a vendor dir.

/assign @raywainman @voelzmo
Marco, Ray, what do you think?

[kwiesmueller]

Another argument from my personal experience with this discussion (I can't count anymore how many projects we had this discussion on), is that CI usually became slower and flakier (network issues) when we relied on the build process pulling the vendors every build. Not sure if we have good enough caching on GitHub.

[fmuyassarov]

Hey folks. I don't have a strong opinion on this nor I don't have a reason to push. If you think it creates problems rather than improving the project, I would say we better close the PR (at least for the time being).
Thanks for your opinions.
/close

[k8s-ci-robot]

@fmuyassarov: Closed this PR.

In response to this:

Hey folks. I don't have a strong opinion on this nor I don't have a reason to push. If you think it creates problems rather than improving the project, I would say we better close the PR (at least for the time being).
Thanks for your opinions.
/close

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