Add HTTPRouteResponseHeaderModification to the conformance tests

Author: kevin85421

conformance/Makefile

@@ -5,7 +5,7 @@ NGINX_PREFIX = $(PREFIX)/nginx
 NGINX_PLUS_PREFIX ?= $(PREFIX)/nginx-plus
 GW_API_VERSION ?= 1.0.0
 GATEWAY_CLASS = nginx
-SUPPORTED_FEATURES = HTTPRouteQueryParamMatching,HTTPRouteMethodMatching,HTTPRoutePortRedirect,HTTPRouteSchemeRedirect,HTTPRouteHostRewrite,HTTPRoutePathRewrite,GatewayPort8080
+SUPPORTED_FEATURES = HTTPRouteQueryParamMatching,HTTPRouteMethodMatching,HTTPRoutePortRedirect,HTTPRouteSchemeRedirect,HTTPRouteHostRewrite,HTTPRoutePathRewrite,GatewayPort8080,HTTPRouteResponseHeaderModification
 KIND_IMAGE ?= $(shell grep -m1 'FROM kindest/node' <tests/Dockerfile | awk -F'[ ]' '{print $$2}')
 KIND_KUBE_CONFIG=$${HOME}/.kube/kind/config
 CONFORMANCE_TAG = latest