The --empty flag (#4966)

## What are you changing in this pull request and why?

Updates the `run` and `build` command references to include the
`--empty` flag.

## Checklist

Uncomment when publishing docs for a prerelease version of dbt:
- [x] Add versioning components, as described in [Versioning
Docs](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/single-sourcing-content.md#versioning-entire-pages)
- [x] Add a note to the prerelease version [Migration
Guide](https://github.com/dbt-labs/docs.getdbt.com/tree/current/website/docs/docs/dbt-versions/core-upgrade)

- [x] Review the [Content style
guide](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/content-style-guide.md)
so my content adheres to these guidelines.
- [x] For [docs
versioning](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/single-sourcing-content.md#about-versioning),
review how to [version a whole
page](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/single-sourcing-content.md#adding-a-new-version)
and [version a block of
content](https://github.com/dbt-labs/docs.getdbt.com/blob/current/contributing/single-sourcing-content.md#versioning-blocks-of-content).

website/docs/docs/dbt-versions/core-upgrade/01-upgrading-to-v1.8.md

@@ -28,7 +28,12 @@ dbt Labs is committed to providing backward compatibility for all versions 1.x,
 
 ## New and changed features and functionality
 
-Coming soon!
+Features and functionality new in dbt v1.8
+
+### The `--empty` flag
+
+The [`run`](/reference/commands/run#the-`--empty`-flag) and [`build`](/reference/commands/build#the---empty-flag) commands now support the `--empty` flag for building schema-only dry runs. The `--empty` flag limits the refs and sources to zero rows. dbt will still execute the model SQL against the target data warehouse but will avoid expensive reads of input data. This validates dependencies and ensures your models will build properly.
+
 
 ## Quick hits
 

website/docs/reference/commands/build.md

@@ -25,6 +25,14 @@ In DAG order, for selected resources or an entire project.
 
 **Flags:** The `build` task supports all the same flags as `run`, `test`, `snapshot`, and `seed`. For flags that are shared between multiple tasks (e.g. `--full-refresh`), `build` will use the same value for all selected resource types (e.g. both models and seeds will be full refreshed).
 
+<VersionBlock firstVersion="1.8">
+
+### The `--empty` flag
+
+The `build` command supports the `--empty` flag for building schema-only dry runs. The `--empty` flag limits the refs and sources to zero rows. dbt will still execute the model SQL against the target data warehouse but will avoid expensive reads of input data. This validates dependencies and ensures your models will build properly.
+
+</VersionBlock>
+
 ### Examples
 
 ```

website/docs/reference/commands/run.md

@@ -80,3 +80,11 @@ See [global configs](/reference/global-configs/failing-fast)
 ## Enable or Disable Colorized Logs
 
 See [global configs](/reference/global-configs/print-output#print-color)
+
+<VersionBlock firstVersion="1.8">
+
+## The `--empty` flag
+
+The `run` command supports the `--empty` flag for building schema-only dry runs. The `--empty` flag limits the refs and sources to zero rows. dbt will still execute the model SQL against the target data warehouse but will avoid expensive reads of input data. This validates dependencies and ensures your models will build properly.
+
+</VersionBlock>