BugFix Modules interface is not serialized as well

Hello, it's seems Modules property on JsonPacket is not serialized like sentry specification require. Instead of
```
{
    "modules": {
        "my.module.name": "1.0"
    }
}
```
Modules is serialized as
```
{
    "modules": [
        { "Name": "my.module.name", "Version": "1.0" }
    ]
}
```