Disable HTTP/2 for webhoook by updating Knative

[khrm]

This disables HTTP/2 for webhook by updating to PR knative/pkg#2875 It fixes CVE-2023-44487.

Changes

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• [ ] Has Docs if any changes are user facing, including updates to minimum requirements e.g. Kubernetes version bumps
• [ ] Has Tests included if any functionality added or changed
• [ ] Follows the commit message standard
• [ ] Meets the Tekton contributor standards (including functionality, content, code)
• [ ] Has a kind label. You can add one by adding a comment on this PR that contains /kind <type>. Valid types are bug, cleanup, design, documentation, feature, flake, misc, question, tep
• [ ] Release notes block below has been updated with any user facing changes (API changes, bug fixes, changes requiring upgrade notices or deprecation warnings). See some examples of good release notes.
• [ ] Release notes contains the string "action required" if the change requires additional action from users switching to the new release

Release Notes

Disable webhook for http2.

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: dibyom

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[savitaashture]

/lgtm

[savitaashture]

/cherry-pick release-v0.25.x

[tekton-robot]

@savitaashture: once the present PR merges, I will cherry-pick it on top of release-v0.25.x in a new PR and assign it to you.

In response to [this](https://github.com/tektoncd/triggers/pull/1672#issuecomment-1812868148): >/cherry-pick release-v0.25.x Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.

[tekton-robot]

@savitaashture: new pull request created: #1675

In response to [this](https://github.com/tektoncd/triggers/pull/1672#issuecomment-1812868148): >/cherry-pick release-v0.25.x Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository.