Update Quickstart to work with MetalLB v 0.14.8

*Description*:
The current https://gateway.envoyproxy.io/latest/tasks/quickstart/ recommends using MetalLB and points to https://metallb.universe.tf/installation/ for installation. The MetalLB installation instructions reference **v0.14.8**, which doesn't work with Envoy Gateway v1.1.1. Connections to HTTPRoutes fail with "no route to host".

I spoke to @arkodg on Slack, and he pointed me to your [CI config](https://github.com/envoyproxy/gateway/blob/main/tools/hack/create-cluster.sh), which uses MetalLB **v0.13.10.** This configuration worked fine for me.

I tested the operation using Gateway API conformance test `HTTPRouteMatching` , e.g.

> go test -v ./conformance --run TestConformance/HTTPRouteMatching --gateway-class=eg --supported-features=Gateway,HTTPRoute --allow-crds-mismatch --cleanup-base-resources=false

producing continuous errors similar to this:

> === NAME TestConformance/HTTPRouteMatching/5_request_to_'/'_with_headers_should_go_to_infra-backend-v2
> http.go:239: 2024-10-02T18:41:15.208537991-04:00: Request failed, not ready yet: Get "http://172. x.y.z/": dial tcp 172.x.y.z:80: connect: no route to host (after 3.377µs)
>

For now, the instructions could say to just use v0.13.10 instead of v0.14.8, but this is just a warning that you may find issues with v0.14.8, even if just running the Gateway API conformance tests.