[REQ][openapi-generator-gradle-plugin] Load inputSpec from classpath

Is your feature request related to a problem? Please describe.

In maven project if I define dependency to a library within plugin I can use a relative path to a inputSpec from the classpath. This is not possible in the current gradle plugin.

Currently there needs to be some workaround with an unpack of a library which is not very convenient.

Describe the solution you'd like

It would be nice if it's possible to reference inputSpec from a classpath
for example:

• I have library file within library openapi-commons => openapi-commons/src/main/resources/commons/openapi.yaml
• I include that library in different poject (e.g. dependencies { api(project(":openapi-commons"))})
• In openApiGenerate (and possibly others) I can the reference inputSpec like inputSpec.set("commons/openapi.yaml")

Describe alternatives you've considered

Additional context

Start at the Gradle plugin's openApiGenerate entry point and trace how the inputSpec value is currently resolved. Verify how a dependency such as openapi-commons is exposed to the plugin, then confirm that inputSpec.set("commons/openapi.yaml") can load the resource without unpacking the library.