Description

When providing an non existing file to the generator, it returns parsing errors instead of a simple message saying "file not found".

It is confusing.

openapi-generator version

0.5.0

OpenAPI declaration file content or url

N/A

Command line used for generation

og unexistingfile.yml markdown

Steps to reproduce

Just run the command.

Related issues/PRs

Suggest a fix/enhancement

What about a message saying: File not found.