[GO][Client] Multipart/form-data Request Support More Than One File (#10843)

* Instead of limiting a request to a single file when
performing an upload, use a slice of files so an
arbitrary number of files can be used in the form.

* Remove commented out line of code

* Update examples for multi-form file fix for multiple files

* Convert spaces to tabs for indentation

* Updated examples to have tabs instead of spaces

* Add an example of a multipart/form-data OA3 schema
that contains two files to be uploaded

samples/openapi3/client/features/mulitple-data-in-forms/docs/ApiResponse.md

@@ -0,0 +1,108 @@
+# ApiResponse
+
+## Properties
+
+Name | Type | Description | Notes
+------------ | ------------- | ------------- | -------------
+**Code** | Pointer to **int32** |  | [optional] 
+**Type** | Pointer to **string** |  | [optional] 
+**Message** | Pointer to **string** |  | [optional] 
+
+## Methods
+
+### NewApiResponse
+
+`func NewApiResponse() *ApiResponse`
+
+NewApiResponse instantiates a new ApiResponse object
+This constructor will assign default values to properties that have it defined,
+and makes sure properties required by API are set, but the set of arguments
+will change when the set of required properties is changed
+
+### NewApiResponseWithDefaults
+
+`func NewApiResponseWithDefaults() *ApiResponse`
+
+NewApiResponseWithDefaults instantiates a new ApiResponse object
+This constructor will only assign default values to properties that have it defined,
+but it doesn't guarantee that properties required by API are set
+
+### GetCode
+
+`func (o *ApiResponse) GetCode() int32`
+
+GetCode returns the Code field if non-nil, zero value otherwise.
+
+### GetCodeOk
+
+`func (o *ApiResponse) GetCodeOk() (*int32, bool)`
+
+GetCodeOk returns a tuple with the Code field if it's non-nil, zero value otherwise
+and a boolean to check if the value has been set.
+
+### SetCode
+
+`func (o *ApiResponse) SetCode(v int32)`
+
+SetCode sets Code field to given value.
+
+### HasCode
+
+`func (o *ApiResponse) HasCode() bool`
+
+HasCode returns a boolean if a field has been set.
+
+### GetType
+
+`func (o *ApiResponse) GetType() string`
+
+GetType returns the Type field if non-nil, zero value otherwise.
+
+### GetTypeOk
+
+`func (o *ApiResponse) GetTypeOk() (*string, bool)`
+
+GetTypeOk returns a tuple with the Type field if it's non-nil, zero value otherwise
+and a boolean to check if the value has been set.
+
+### SetType
+
+`func (o *ApiResponse) SetType(v string)`
+
+SetType sets Type field to given value.
+
+### HasType
+
+`func (o *ApiResponse) HasType() bool`
+
+HasType returns a boolean if a field has been set.
+
+### GetMessage
+
+`func (o *ApiResponse) GetMessage() string`
+
+GetMessage returns the Message field if non-nil, zero value otherwise.
+
+### GetMessageOk
+
+`func (o *ApiResponse) GetMessageOk() (*string, bool)`
+
+GetMessageOk returns a tuple with the Message field if it's non-nil, zero value otherwise
+and a boolean to check if the value has been set.
+
+### SetMessage
+
+`func (o *ApiResponse) SetMessage(v string)`
+
+SetMessage sets Message field to given value.
+
+### HasMessage
+
+`func (o *ApiResponse) HasMessage() bool`
+
+HasMessage returns a boolean if a field has been set.
+
+
+[[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
+
+

samples/openapi3/client/features/mulitple-data-in-forms/docs/DefaultApi.md

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+# \DefaultApi
+
+All URIs are relative to *http://example.com*
+
+Method | HTTP request | Description
+------------- | ------------- | -------------
+[**UploadFiles**](DefaultApi.md#UploadFiles) | **Post** /uploadFiles | uploads two files
+
+
+
+## UploadFiles
+
+> ApiResponse UploadFiles(ctx).File(file).SecondFile(secondFile).Execute()
+
+uploads two files
+
+### Example
+
+```go
+package main
+
+import (
+    "context"
+    "fmt"
+    "os"
+    openapiclient "./openapi"
+)
+
+func main() {
+    file := os.NewFile(1234, "some_file") // *os.File | file to upload (optional)
+    secondFile := os.NewFile(1234, "some_file") // *os.File | another file to upload (optional)
+
+    configuration := openapiclient.NewConfiguration()
+    api_client := openapiclient.NewAPIClient(configuration)
+    resp, r, err := api_client.DefaultApi.UploadFiles(context.Background()).File(file).SecondFile(secondFile).Execute()
+    if err != nil {
+        fmt.Fprintf(os.Stderr, "Error when calling `DefaultApi.UploadFiles``: %v\n", err)
+        fmt.Fprintf(os.Stderr, "Full HTTP response: %v\n", r)
+    }
+    // response from `UploadFiles`: ApiResponse
+    fmt.Fprintf(os.Stdout, "Response from `DefaultApi.UploadFiles`: %v\n", resp)
+}
+```
+
+### Path Parameters
+
+
+
+### Other Parameters
+
+Other parameters are passed through a pointer to a apiUploadFilesRequest struct via the builder pattern
+
+
+Name | Type | Description  | Notes
+------------- | ------------- | ------------- | -------------
+ **file** | ***os.File** | file to upload | 
+ **secondFile** | ***os.File** | another file to upload | 
+
+### Return type
+
+[**ApiResponse**](ApiResponse.md)
+
+### Authorization
+
+No authorization required
+
+### HTTP request headers
+
+- **Content-Type**: multipart/form-data
+- **Accept**: application/json
+
+[[Back to top]](#) [[Back to API list]](../README.md#documentation-for-api-endpoints)
+[[Back to Model list]](../README.md#documentation-for-models)
+[[Back to README]](../README.md)
+