docs: Document the retain feature

docs/web-apps/automated-testing/cypress/yaml/v1.md

@@ -613,10 +613,13 @@ Specifies how to manage test artifacts, such as logs, videos, and screenshots.
 ```yaml
 artifacts:
   cleanup: true
+  retain:
+    generated-report-dir: report.zip
   download:
     when: always
     match:
       - junit.xml
+      - report.zip
     directory: ./artifacts/
 ```
 
@@ -635,6 +638,35 @@ artifacts:
 
 ---
 
+### `retain`
+
+<p><small>| OPTIONAL | OBJECT |</small></p>
+
+Define directories to archive and retain as a test asset at the end of a test run. Archived test assets can
+be downloaded automatically using the `download` configuration or via the 
+[REST API](https://docs.saucelabs.com/dev/api/jobs/#get-a-job-asset-file) or through the test details page.
+
+```yaml
+artifacts:
+  retain:
+    source-directory: destination-archive.zip
+  download:
+    when: always
+    match:
+      - destination-archive.zip
+    directory: ./artifacts/
+```
+
+:::note
+The source and destination will be relative to the `rootDir` defined in your configuration.
+:::
+
+:::note
+The destination archive must have a .zip file extension.
+:::
+
+---
+
 ### `download`
 
 <p><small>| OPTIONAL | OBJECT |</small></p>