feat: remove outdated PHP gRPC build instructions from makefile

makefile

@@ -13,17 +13,6 @@ help:
 	@echo "  enable-coverage 	- Enable PCOV code coverage in the composer runtime container"
 	@echo "  protoc        		- Generate PHP gRPC code from .proto files"
 
-
-build-php-grpc:
-	git clone -b v1.76.0 https://github.com/grpc/grpc
-	cd grpc
-	cd grpc && git submodule update --init
-	grpc_root="$(pwd)"
-	cd src/php/ext/grpc
-	phpize
-	GRPC_LIB_SUBDIR=libs/opt ./configure --enable-grpc="${grpc_root}"
-	make
-
 composer-install:
 	docker compose exec composer-runtime sh -c "composer install --no-interaction --prefer-dist --optimize-autoloader --ignore-platform-reqs"