Add ISTIO_META_ISTIO_VERSION for EnvoyFilters

EnvoyFilters require that the proxyv2 images have the env ISTIO_META_ISTIO_VERSION. Without this we cannot apply EnvoyFilters to services.

Here is the dockerfile https://github.com/istio/istio/blob/master/pilot/docker/Dockerfile.proxyv2#L33-L36

https://istio.io/latest/docs/reference/config/networking/envoy-filter/#EnvoyFilter-ProxyMatch