Add sandbox.lifecycle.checkpointed event to lifecycle docs

New webhook/API event type for when a snapshot is created from a sandbox.

Author: dobrac

docs/sandbox/lifecycle-events-api.mdx

@@ -3,7 +3,7 @@ title: "Monitor sandbox lifecycle Events"
 sidebarTitle: Lifecycle events API
 ---
 
-The lifecycle API provides RESTful endpoints to request the latest sandbox lifecycle events. This allows you to track when sandboxes are created, paused, resumed, updated, or killed, along with metadata.
+The lifecycle API provides RESTful endpoints to request the latest sandbox lifecycle events. This allows you to track when sandboxes are created, paused, resumed, updated, checkpointed, or killed, along with metadata.
 All requests require authentication using your team [API key](/docs/api-key#where-to-find-api-key).
 
 Query Parameters:

docs/sandbox/lifecycle-events-webhooks.mdx

@@ -346,4 +346,5 @@ The following event types can be subscribed to via webhooks, they are used as th
 - `sandbox.lifecycle.updated` - Sandbox configuration updates
 - `sandbox.lifecycle.paused` - Sandbox pausing
 - `sandbox.lifecycle.resumed` - Sandbox resuming
+- `sandbox.lifecycle.checkpointed` - Sandbox [snapshot](/docs/sandbox/snapshots) created