chore: Update update karpenter addon to v0.20.0

[armujahid]

What does this PR do?

update karpenter to v0.20.0

Motivation

Improvements and fixes. Specially multi-node consolidation

More

• Yes, I have tested the PR using my local account setup (Provide any test evidence report under Additional Notes)
• Yes, I have added a new example under examples to support my PR
• Yes, I have created another PR for add-ons under add-ons repo (if applicable)
• Yes, I have updated the docs for this feature
• Yes, I ran pre-commit run -a with this PR

Note: Not all the PRs require a new example and/or doc page. In general:

• Use an existing example when possible to demonstrate a new addons usage
• A new docs page under docs/add-ons/* is required for new a new addon

For Moderators

• E2E Test successfully complete before merge?

Additional Notes

Karpenter example deployment:
tested karpenter example with terraform v1.3.6 using sample_deployment_lt.yaml and sample_deployment.yaml
and all 6 pods were successfully scheduled from both deployments.

Note that karpenter only seems to work if we provision 2 managed nodes (one instance per node). It wasn't provisioning nodes with just one managed node (which is kind of strange since one pod of karpenter should also work in my opinion. Related #990). Anyways, I think I should also update karpenter example in a seperate PR (managed node desired_size = 2)