No diagnostics reported on empty files

[jeffmaury]

Describe the bug

Created an empty devfile.yaml whose corresponding schema is here: https://github.com/devfile/api/releases/download/v2.0.0/devfile.json

Expected Behavior

I would expect diagnostics to be reported as schemaVersion is a required property

Current Behavior

No error reported

Steps to Reproduce

1. add in yaml.schemas: "https://github.com/devfile/api/releases/download/v2.0.0/devfile.json":"devfile.y*ml"
2. create a devfile.yaml file
3. open the file

Environment

• Windows
• Mac
• Linux
• other (please specify)