Update getting started guide with 1.0 release

[rahulgurnani]

What type of PR is this?

/kind documentation

What this PR does / why we need it:
Bumping up docs to 1.0 release

Which issue(s) this PR fixes:

Fixes #1464

Does this PR introduce a user-facing change?:

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[k8s-ci-robot]

Hi @rahulgurnani. 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.

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[kfswain]

/ok-to-test

Looks great, thanks @rahulgurnani just giving the tests a chance to pass

[kfswain]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: kfswain, rahulgurnani

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[nirrozenbaum]

this lgtm.
can we add this update to the release script (only for final release, not for RCs), so we don't need to manually update it after every release?

we have an issue opened for that #1494