Add e2e tests for HTTP2 Server-Side Push

[tanzeeb]

In what area(s)?

/area networking
/area test-and-release
/kind good-first-issue

Describe the feature

The HTTP2 spec allows for server-side push, which allows the server to "push" resources to the client without an explicit request. We need an e2e test to ensure that this functionality works in Knative.

For more information on the feature, and how to implement it in Go, see this post:

https://blog.golang.org/h2push

[tanzeeb]

/assign

[tanzeeb]

Update: looks like push promises aren't yet supported by the the Go http/2 client.

This impacts both the ability to test the feature, and the actual support of the feature since the ReverseProxy in the Activator and Queue-Proxy both use the go http/2 client.

This story is blocked until golang/go#18594 is addressed.

/unassign

[knative-housekeeping-robot]

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Mark the issue as fresh by adding the comment /remove-lifecycle stale.
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If this issue is safe to close now please do so by adding the comment /close.

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/lifecycle stale

[knative-housekeeping-robot]

Stale issues rot after 30 days of inactivity.
Mark the issue as fresh by adding the comment /remove-lifecycle rotten.
Rotten issues close after an additional 30 days of inactivity.
If this issue is safe to close now please do so by adding the comment /close.

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/lifecycle rotten

[knative-housekeeping-robot]

Rotten issues close after 30 days of inactivity.
Reopen the issue with /reopen.
Mark the issue as fresh by adding the comment /remove-lifecycle rotten.

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/close

[knative-prow-robot]

@knative-housekeeping-robot: Closing this issue.

In response to this:

Rotten issues close after 30 days of inactivity.
Reopen the issue with /reopen.
Mark the issue as fresh by adding the comment /remove-lifecycle rotten.

Send feedback to Knative Productivity Slack channel or file an issue in knative/test-infra.

/close

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