Add envoy-gateway as a release artifact #4566
Description
similar to envoyproxy https://github.com/envoyproxy/envoy/releases/tag/v1.32.0 , imo `linux-x86_64` is good enough for now
Originally posted by @arkodg in #4518 (comment)