🌱 e2e: add option to configure both control-plane and workers machine template for k8s upgrade tests

[cpanato]

What this PR does / why we need it:

• add option to configure both control-plane and workers machine template for k8s upgrade tests

/assign @fabriziopandini @sbueringer

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Follow up of #6075 (comment)

[sbueringer]

Thank you very much!
/lgtm

I think we should cherry-pick this to release-1.1 too, like the previous PR which added the first env var (otherwise it's just annoying to configure main and 1.1 e2e tests differently)
/cherry-pick release-1.1

I think it's fine that we replace the existing env var, given the stability guarantees we have for the test framework
@aartij17 @srm09 Please note that you have to update your jobs to the new env vars once you pick up this change.

/assign @fabriziopandini

[k8s-infra-cherrypick-robot]

@sbueringer: once the present PR merges, I will cherry-pick it on top of release-1.1 in a new PR and assign it to you.

In response to this:

Thank you very much!
/lgtm

I think we should cherry-pick this to release-1.1 to, like the previous PR which added the first env var (otherwise it's just annoying to configure main and 1.1 e2e tests differently)
/cherry-pick release-1.1

I think it's fine that we replace the existing env var, given the stability guarantees we have for the test framework
@aartij17 @srm09 Please note that you have to update your jobs to the new env vars once you pick up this change.

/assign @fabriziopandini

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[enxebre]

/lgtm

[sbueringer]

@fabriziopandini PTAL, when you have some bandwidth.

[killianmuldoon]

/lgtm

[fabriziopandini]

Thanks @cpanato for this improvement!
Hopefully, when switching to ClusterClass things will be simplified a little bit, but for now it is great to support this

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: fabriziopandini

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• OWNERS [fabriziopandini]

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[k8s-infra-cherrypick-robot]

@sbueringer: new pull request created: #6242

In response to this:

Thank you very much!
/lgtm

I think we should cherry-pick this to release-1.1 too, like the previous PR which added the first env var (otherwise it's just annoying to configure main and 1.1 e2e tests differently)
/cherry-pick release-1.1

I think it's fine that we replace the existing env var, given the stability guarantees we have for the test framework
@aartij17 @srm09 Please note that you have to update your jobs to the new env vars once you pick up this change.

/assign @fabriziopandini

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.