[BUG] OpenAPI Generator fails to generate array models

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

OpenAPI generator fails to generate array models. It complains with:

[main] INFO  o.o.codegen.DefaultGenerator - Model {} not generated since it's an alias to array (without property) and `generateAliasAsModel` is set to false (default)

openapi-generator version

v4.3.1

And also tried latest master using Docker 07c23f4d1ad184554968b1bbe858b4ad987dd698.

OpenAPI declaration file content or url

openapi: '3.0.3'

info:
  title: Test
  version: 0.1.0

paths: {}

components:
  schemas:
    Test:
      type: array
      items:
        type: object
        properties:
          foo:
            type: string

Generation Details

docker run --rm \                                
  -v ${PWD}:/local openapitools/openapi-generator-cli generate \    
  -i /local/openapi.yaml \ 
  -g go \
  -o /local/out/go

Steps to reproduce

1. Generate a client for any language using the provided schema. Note that the array model is not generated with the log message from this bug's description.

Related issues/PRs

Suggest a fix

The following code is erroneous. An array has items not properties (Even required by the OpenAPI spec). You might need to cast Schema to ArraySchema to get access to items or something like that.
https://github.com/OpenAPITools/openapi-generator/blob/41851b45e1f1ffa7f0df36270a6b3c0cee6425bb/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java#L485-L488

Reproduce the issue with the provided OpenAPI YAML and Docker generation command. Start at modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java around lines 485-488, comparing array schemas' items with properties. Done means the Test array model is generated instead of being skipped as an alias.