Fix documentation about of batch_size supported values and default

Our docs stated that we only support `day`, but we support `hour`, `day`,
`month`, and `year`. Our docs also stated that `batch_size` will be defaulted
to `day`. This is not true, it is a required value and will not be defaulted.

website/docs/docs/build/incremental-microbatch.md

@@ -162,7 +162,7 @@ Several configurations are relevant to microbatch models, and some are required:
 |----------|------|---------------|---------|
 | `event_time` | Column  (required)   | The column indicating "at what time did the row occur." Required for your microbatch model and any direct parents that should be filtered.          | N/A     |
 | `begin`      | Date (required)   | The "beginning of time" for the microbatch model. This is the starting point for any initial or full-refresh builds. For example, a daily-grain microbatch model run on `2024-10-01` with `begin = '2023-10-01` will process 366 batches (it's a leap year!) plus the batch for "today."        | N/A     |
-| `batch_size` | String (required)  | The granularity of your batches. The default is `day` (and currently this is the only granularity supported).             | `day`   |
+| `batch_size` | String (required)  | The granularity of your batches. Supported values are `hour`, `day`, `month`, and `year`             | N/A     |
 | `lookback`   | Integer (optional) | Process X batches prior to the latest bookmark to capture late-arriving records.                                         | `0`     |
 
 <Lightbox src="/img/docs/building-a-dbt-project/microbatch/event_time.png" title="The event_time column configures the real-world time of this record"/>