Databroker: No timestamps for target values

[SebastianSchildt]

What happens

When querying target values, the Datapoints contain no timestamp

Expectation

When querying a target value there is a timestamp denoting when that target value was that. This timestamp is independent from current value timestamp, i.e. a single datapoint can (will) have different timestamps for both values

Reproduce

import asyncio

from kuksa_client.grpc import Datapoint
from kuksa_client.grpc.aio import VSSClient

async def main():
    async with VSSClient('127.0.0.1', 55556) as client:
        await client.set_target_values({
            'Vehicle.Body.Windshield.Front.Wiping.System.TargetPosition': Datapoint(45),
        })

        current_values = await client.get_target_values([
            'Vehicle.Body.Windshield.Front.Wiping.System.TargetPosition',
        ])
        print(current_values)

asyncio.run(main())

gives

{'Vehicle.Body.Windshield.Front.Wiping.System.TargetPosition': Datapoint(value=45.0, timestamp=None)}

[SebastianSchildt]

Fixed by #474