Update docs to note schedule action delay (#3059) (#3060)

* Update docs to note schedule action delay (#3059)

The schedule action start time delay is significant (up to an hour) and warrants a mention to save people time thinking it's something they are doing incorrectly

* Apply suggestions from code review

Co-authored-by: Sarah Edwards <skedwards88@github.com>

Author: BrentonWheeler

content/actions/reference/events-that-trigger-workflows.md

@@ -41,6 +41,12 @@ The following steps occur to trigger a workflow run:
 
 The `schedule` event allows you to trigger a workflow at a scheduled time.
 
+{% note %}
+
+Note: Due to load, the `schedule` event may be delayed 
+
+{% endnote %}
+
 #### `schedule`
 
 | Webhook event payload | Activity types | `GITHUB_SHA` | `GITHUB_REF` |