Update Envoy examples to V3 API?

[dfeldman]

All our Envoy examples use the config file format "V2," which was discontinued at the end of 2020. New Envoy versions (1.17 and 1.18) support it through a backward compatibility mode that is not very reliable and will go away in the future. Should we update these? The disadvantage is that users currently on 1.13 would no longer have a configuration reference.

[rturner3]

It seems like it would be helpful to include references for both the v2 and v3 Envoy config formats. Perhaps each set of config examples (v2 and v3) could indicate the corresponding versions of Envoy they are compatible with?

[dfeldman]

I did some personal notes on Envoy configuration here: https://github.com/dfeldman/envoy-notes/blob/main/envoy_configuration.md . They are definitely not polished enough to be official documentation but may be helpful.