kubeflow-pipelines: upgrade envoy config

[xnox]

Upstream ships https://github.com/kubeflow/pipelines/commits/master/third_party/metadata_envoy/envoy.yaml which is used in their dockerfile under the name envoy.yaml

From history, we packaged this file under a different name always, and our image has always used it under a different name. Not sure why.

Also the contents of our statically vendored config, doesn't seem to match any versions or copies of the upstream envoy.yaml config. Not sure if this is intentional (because our envoy is different) or original enovy.yaml was taken from somewhere else (i.e. some other repo or docs).

Also I don't know what this does, but imho we should attempt to upgrade to upstream config of envoy for this image.

This was noticed by @justinvreeland here.

TODO: test image release with this update

[github-actions[bot]]

This Pull Request is stale because it has been open for 90 days with no activity. It will automatically close after 30 more days of inactivity. Keep fresh with the 'lifecycle/frozen' label.