Update kubectl_path_documents example doc.

[GezimSejdiu]

Example uses kubectl_file_documents instead of kubectl_path_documents.
for_each has to be a set or a map and thus toset() is needed.
This update closes #135.

[gavinbunney]

Thanks!

[GezimSejdiu]

Thank you and everyone for contributing to such a great tool. Keep it up.

[indistinctTalk]

The use of documents with for_each is confusing given the advice in the attribute documentation below.

* `manifests` - Map of YAML documents with key being the document id, and value being the document yaml. Best used with `for_each` expressions.
* `documents` - List of YAML documents (list[string]). Best used with `count` expressions.

Should it actually be manifests or?

[rverchere]

Hi,

Prefer using:

for_each   = data.kubectl_path_documents.sa_manifests_docs.manifests
yaml_body  = each.value

Which produces a human readable resource, i.e. kubectl_manifest.sa_manifests["/api/v1/namespaces/kube-system/serviceaccounts/gitlab"]

Instead of:

for_each   = toset(data.kubectl_path_documents.sa_manifests_docs.documents)
yaml_body  = each.value

Because it produces an unreadable resource, i.e. kubectl_manifest.sa_manifests["apiVersion: rbac.authorization.k8s.io/v1\nkind: RoleBinding\nmetadata:\n name: gitlab\n namespace: gitlab\nsubjects:\n - kind: ServiceAccount\n name: gitlab\n namespace: kube-system\nroleRef:\n apiGroup: rbac.authorization.k8s.io\n kind: ClusterRole\n name: cluster-admin"]

Should the documentation be updated accordingly?