[BUG][GO] go-server does not correctly handle optional query params for boolean and string array types

Created by: mpapale

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?
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Description

Optional query parameters of type boolean or string array, e.g.

parameters:
  - name: myFlag
    required: false
    in: query
    schema:
      type: boolean
  - name: myStrings
    required: false
    in: query
    schema:
      type: array
      items:
        type: string

are not being generated properly via the templates, causing a 500 error if they are not provided in the HTTP call.

openapi-generator version

5.1.1 I don't believe this is a regression.

OpenAPI declaration file content or url

openapi: 3.0.0
info:
  description: 'OpenAPI Petstore'
  title: OpenAPI Petstore
  version: 1.0.0
servers:
- description: The local server
  url: https://localhost:8080/{version}
paths:
  /pets:
    get:
      operationId: getPet
      parameters:
      - description: Only return pets with these tag names
        in: query
        name: tagNames
        required: false
        schema:
          type: array
          items:
            type: string
      - description: Only return pets with available status
        in: query
        name: isAvailable
        required: false
        schema:
          type: boolean
      responses:
        "200":
          content: {}
          description: ""

Generation Details

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

Steps to reproduce

Generate the code and look in the routers.go file for parseBoolParameter which does not have a required flag. Also notice there is no parseStringArrayParameter function, so api_pets.go will do a strings.Split on tagNames. If tagNames is not provided, it will be set to [""] which is incorrect.