Clean up .travis.yaml

[ialidzhikov]

Is this a bug fix or adding new feature?
/kind cleanup

What is this PR about? / Why do we need it?
I assume that this project is no longer using Travis CI. At least, I no longer see a travis check/job on PRs.
Hence, this PR removes the .travis.yaml.

What testing is done?

[ialidzhikov]

/cc @wongma7

[k8s-ci-robot]

Hi @ialidzhikov. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[ConnorJC3]

/ok-to-test

/lgtm

[torredil]

/lgtm

[gtxu]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gtxu

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