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

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

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.

Related issues/PRs

Suggest a fix

Generate the go-server output with the provided OpenAPI declaration and inspect routers.go and api_pets.go. Start at parseBoolParameter and the string-array handling described in the issue. Done means omitted optional boolean and string-array query parameters no longer cause a 500 or produce an array containing an empty string.