[BUG] can't find schema no matter how I write the (valid) filename

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

When I try to use openapi-generator-cli to generate a schema, it always gives me the "The spec file is not found" error, even though the filename I pass in is valid.

openapi-generator version

openapi-generator-cli 7.8.0
commit : 6bdc452
built : -999999999-01-01T00:00:00+18:00
source : https://github.com/openapitools/openapi-generator
docs : https://openapi-generator.tech/

OpenAPI declaration file content or url

This happens with any spec I try to use. I've tried with both the stripe as well as one produced by Kanidm.

Generation Details

I get this error even with a simple generator request like openapi-generatorcli generate -g cpp-restsdk -o stripe-cpp -i spec3.json (for stripe).

Steps to reproduce

1. Install openapi-generator-cli with scoop
2. Try generating any OpenAPI client implementation from a spec and you should get the error. Also, validation doesn't work either; the system assumes that the spec is a JAR or should be on the classpath or something.

Related issues/PRs

Suggest a fix

Start by reproducing the command shown with openapi-generator-cli 7.8.0 and the referenced Stripe or Kanidm specification. Check the generate and validation entry points for how the input filename is resolved. Done means a valid local OpenAPI file is found and accepted instead of reported as missing.