Bump Echoserver Image Tag

[danehans]

kubernetes-sigs/gateway-api#1520 bumps the echoserver image version in conformance tests. When #717 is merged, it should cause Gateway API conformance tests in EG to use the new image tag. The image tag should be bumped to v20221109-7ee2f3e in user docs for consistency.

[Xunzhuo]

I am going to bump this after kubernetes-sigs/gateway-api#1520 got merged. ResponseHeaderModifier Filter needs to use this new echo-server to demonstrate response header modifying abilities.

[danehans]

ResponseHeaderModifier Filter needs to use this new echo-server to demonstrate response header modifying abilities

Yes, the image tag for the conformance tests should get bumped as part of bumping Gateway API. This issue targets the image tag used by the user docs that will not get bumped without manual intervention.