BUG/MINOR: use int64 format for memory information

[jmdelafe]

It defaults to int32 when not specified, and that is not enough for modern machines with way more than 2 GB of memory.

[mjuraga]

What is the exact issue, as they are generated as int64 here: https://github.com/haproxytech/client-native/blob/master/models/info.go#L443

[jmdelafe]

I found the issue when building a Data Plane API (v3) client for Go. I used https://openapi-generator.tech/ to build it.

# snippet from model_info_system_mem_info.go
// InfoSystemMemInfo struct for InfoSystemMemInfo
type InfoSystemMemInfo struct {
	DataplaneapiMemory *int32 `json:"dataplaneapi_memory,omitempty"`
	FreeMemory *int32 `json:"free_memory,omitempty"`
	TotalMemory *int32 `json:"total_memory,omitempty"`
}