in KubernetesPodOperator the name parameter is mandatory.
However if you forget to add it you will get a broken dag message with:
![Screen Shot 2021-04-12 at 12 16 58](https://user-images.githubusercontent.com/62940116/114373136-f699d180-9b8a-11eb-8500-d8e7118650ae.png)

This is because
https://github.com/apache/airflow/blob/1dfbb8d2031cb8a3e95e4bf91aa478857c5c3a85/airflow/providers/cncf/kubernetes/operators/kubernetes_pod.py#L277

it calls validate_data which produce this error:
https://github.com/apache/airflow/blob/1dfbb8d2031cb8a3e95e4bf91aa478857c5c3a85/airflow/utils/helpers.py#L40

The error is not useful. It doesn't explain what the issue is of where the problem is. it also says problem with `key` which isn't a parameter of anything.
I couldn't even know that the issue is from the KubernetesPodOperator.

Suggestions:
make better error message for `KubernetesPodOperator` when name parameter is missing OR invalid.

I would also suggest to make validate_key produce a better error message specifying what object produce the error
airflow/providers/cncf/kubernetes/operators/kubernetes_pod.py
self.dnspolicy = dnspolicy
        self.schedulername = schedulername
        self.full_pod_spec = full_pod_spec
        self.init_containers = init_containers or []
        self.log_events_on_failure = log_events_on_failure
        self.priority_class_name = priority_class_name
        self.pod_template_file = pod_template_file
        self.name = self._set_name(name)
        self.termination_grace_period = termination_grace_period
        self.client: CoreV1Api = None
        self.pod: k8s.V1Pod = None
    def _render_nested_template_fields(
        self,
        content: Any,
        context: Dict,
        jinja_env: "jinja2.Environment",
        seen_oids: set,
    ) -> None:
        if id(content) not in seen_oids and isinstance(content, k8s.V1EnvVar):
            seen_oids.add(id(content))
            self._do_render_template_fields(content, ('value', 'name'), context, jinja_env, seen_oids)
            return
        super()._render_nested_template_fields(
            content,
            context,
            jinja_env,
            seen_oids
        )
    @staticmethod
    def create_labels_for_pod(context) -> dict: