Support multiple documents in yaml files

[nikolaik]

Quick hack to see how much work it would be ref #222

The output is a bit unintuitive atm, but could probably be improved:

$ cat catalog-info.yaml --- apiVersion: backstage.io/v1alpha1 kind: System metadata:  name: example-system spec:  owner: my-team --- apiVersion: backstage.io/v1alpha1 kind: Component metadata:  name: example-service spec:  owner: my-team  system: example-system $ check-jsonschema --schemafile "https://json.schemastore.org/catalog-info.json" -v catalog-info.yaml Schema validation errors were encountered.  yolo.yaml::$: {'apiVersion': 'backstage.io/v1alpha1', 'kind': 'Component', 'metadata': {'name': 'example-service'}, 'spec': {'owner': 'my-team', 'system': 'example-system'}} is not valid under any of the given schemas  Underlying errors caused this.  Best Match:  $.kind: 'Component' is not one of ['API']  All Errors:  $.kind: 'Component' is not one of ['API']  $.spec: 'type' is a required property  $.spec: 'lifecycle' is a required property  $.spec: 'definition' is a required property  $.spec: 'type' is a required property  $.spec: 'lifecycle' is a required property  $.kind: 'Component' is not one of ['Domain']  $.kind: 'Component' is not one of ['Group']  $.spec: 'type' is a required property  $.spec: 'children' is a required property  $.kind: 'Component' is not one of ['Location']  $.kind: 'Component' is not one of ['Resource']  $.spec: 'type' is a required property  $.kind: 'Component' is not one of ['System']  $.apiVersion: 'backstage.io/v1alpha1' is not one of ['backstage.io/v1beta2']  $.kind: 'Component' is not one of ['Template']  $.spec: 'type' is a required property  $.spec: 'steps' is a required property  $.kind: 'Component' is not one of ['User']  $.spec: 'memberOf' is a required property