[BUG][AVRO] String of type byte is not well converted to Avro Bytes format

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 trying to generate an Avro schema from an open api spec that contains a type string with format byte, the corresponding generated type is "mode.Bytes" instead of "bytes".

    {
      "name": "certi",
      "type": ["null", "model.Bytes"],
      "doc": "Base64 encoded certificate",
      "default": null
    }

instead of

    {
      "name": "certi",
      "type": ["null", "bytes"],
      "doc": "Base64 encoded certificate",
      "default": null
    }

openapi-generator version

openapi-generator-cli 7.10.0
commit : 12dfe8f

OpenAPI declaration file content or url

openapi: 3.0.1
info:
  title: Sample API
  description: Optional multiline or single-line description in [CommonMark](http://commonmark.org/help/) or HTML.
  version: 0.1.9

servers:
  - url: http://api.example.com/v1
    description: Optional server description, e.g. Main (production) server
  - url: http://staging-api.example.com
    description: Optional server description, e.g. Internal staging server for testing

paths:
  /users:
    get:
      summary: Returns a list of users.
      description: Optional extended description in CommonMark or HTML.
      responses:
        "200": # status code
          description: A JSON array of user names
          content:
            application/json:
              schema:
                type: array
                items:
                  type: string
components:
  schemas:
    Alert:
      type: object
      properties:
        certi:
          description: Base64 encoded certificate
          type: string
          format: byte

Steps to reproduce

openapi-generator-cli generate -g avro-schema -i resources/test/openapi-spec.yaml -o test

Related issues/PRs

Suggest a fix

I'd be happy to try to fix it, but I'm fairly new to mustach template within openapi generator.

Run the shown avro-schema generation command with resources/test/openapi-spec.yaml and compare the generated schema for Alert.certi. Start by tracing the Avro-schema generator's Mustache template or mapping that produces model.Bytes. Done means a string with format byte generates Avro type bytes, with coverage for this reproduction.