bug: create ApisixRoute failed by k8s dynamic client-go

[jianghushinian]

bug: create ApisixRoute failed by k8s dynamic client-go

[Revolyssup]

@acuteaura I think the change is meaningful enough that we can introduce it even if it is breaking. Replacing these fields as pointers looks good to me. The consumers should be able to upgrade to newer version with code changes. @AlinsRan What do you think?

[jianghushinian]

if wrote:

func buildK8sApisixRoute(name, namespace string, port int32) *apisixv2.ApisixRoute {
	return &apisixv2.ApisixRoute{
		TypeMeta: metav1.TypeMeta{
			APIVersion: "apisix.apache.org/v2",
			Kind:       "ApisixRoute",
		},
		ObjectMeta: metav1.ObjectMeta{
			Name:      name,
			Namespace: namespace,
		},
		Spec: apisixv2.ApisixRouteSpec{
			HTTP: []apisixv2.ApisixRouteHTTP{
				{
					Name: name,
					Match: apisixv2.ApisixRouteHTTPMatch{
						Hosts: []string{"xxx"},
						Paths: []string{"/*"},
					},
					Backends: []apisixv2.ApisixRouteHTTPBackend{
						{
							ServiceName: name,
							ServicePort: intstr.IntOrString{
								Type:   intstr.Int,
								IntVal: port,
							},
						},
					},
					Authentication: apisixv2.ApisixRouteAuthentication{
						Enable: false,
						Type:   "basicAuth",
					},
				},
			},
		},
	}
}

will success.

the following code is necessary, but useless, if we should use pointers to avoid mandatory parameters？

Authentication: apisixv2.ApisixRouteAuthentication{
		Enable: false,
		Type:   "basicAuth",
	}

[acuteaura]

There's a lot more of these that have omitempty but can can't marshall from Go as nil values. Would suggest we fix these in a big swoop (being mindful of possible NPE) since it breaks other library API consumers.