Meltano

Hey folks,
In the Meltano docs it says that _inline stream maps_ can be used to override the key_properties, to allow you enable append-only behaviour at a target. I've developed a tap, using the Meltano SDK, and it's working fine, but can't get the stream maps to set the `key_properties` in the catalog/schema out to null. I'm setting the stream map in the meltano config, as described <https://sdk.meltano.com/en/latest/stream_maps.html#unset-or-modify-the-stream-s-primary-key-behavior|here> but it isn't resulting in the desired behaviour.

When I output the `invoke` comand I can see the property isn't overwritten to be null or empty.

What does your `stream_maps` config look like?

```    config:
      stream_maps:
        campaigns:
          __key_properties__: null```

(<https://github.com/meltano/meltano/issues/6382> may be at fault)