Add specification for check in connector sync job (#3365)

(cherry picked from commit ca214ff)

specification/connector/sync_job_check_in/SyncJobCheckInRequest.ts

@@ -0,0 +1,39 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import { RequestBase } from '@_types/Base'
+import { Id } from '@_types/common'
+
+/**
+ * Check in a connector sync job.
+ * Check in a connector sync job and set the `last_seen` field to the current time before updating it in the internal index.
+ *
+ * To sync data using self-managed connectors, you need to deploy the Elastic connector service on your own infrastructure.
+ * This service runs automatically on Elastic Cloud for Elastic managed connectors.
+ * @rest_spec_name connector.sync_job_check_in
+ * @availability stack stability=experimental visibility=public
+ * @doc_id connector-sync-job-checkin
+ */
+export interface Request extends RequestBase {
+  path_parts: {
+    /**
+     * The unique identifier of the connector sync job to be checked in.
+     */
+    connector_sync_job_id: Id
+  }
+}

specification/connector/sync_job_check_in/SyncJobCheckInResponse.ts

@@ -0,0 +1,22 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+export class Response {
+  body: {}
+}